diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..57872d0
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+/vendor/
diff --git a/bin/github-sync-website-shared b/bin/github-sync-website-shared
new file mode 100644
index 0000000..0456cc3
--- /dev/null
+++ b/bin/github-sync-website-shared
@@ -0,0 +1,93 @@
+#!/usr/bin/env php
+<?php
+
+use Amp\Artax\Client;
+use Amp\Artax\DefaultClient;
+use Amp\ByteStream\ResourceInputStream;
+use Amp\ByteStream\ResourceOutputStream;
+use Amp\Loop;
+use Amp\WebsiteTools\GitHubClient;
+use Kelunik\OAuth\Providers\GitHub;
+use function Kelunik\OAuthCli\authenticate;
+
+require __DIR__ . "/../vendor/autoload.php";
+
+$clientId = getenv("AMPHP_GITHUB_SYNC_APP_ID");
+$clientSecret = getenv("AMPHP_GITHUB_SYNC_APP_SECRET");
+
+Loop::run(function () use ($clientId, $clientSecret) {
+    $stdin = new ResourceInputStream(STDIN);
+    $stdout = new ResourceOutputStream(STDOUT);
+
+    $httpClient = new DefaultClient;
+    $httpClient->setOption(Client::OP_DEFAULT_HEADERS, [
+        "user-agent" => "amphp/website-tools",
+    ]);
+
+    $github = new GitHub($httpClient, "http://127.0.0.1:1337/oauth", $clientId, $clientSecret, ["repo"]);
+    $oauthToken = yield authenticate($github);
+
+    $githubClient = new GitHubClient($oauthToken, $httpClient);
+
+    $reference = yield $githubClient->getHead("amphp/website-shared", "master");
+
+    yield $stdout->write("amphp/website-shared is at {$reference}\r\n");
+    yield $stdout->write("Do you want to update all repositories to that reference? [y/N]: ");
+    $answer = yield $stdin->read();
+
+    if (trim($answer) !== "y") {
+        exit(0);
+    }
+
+    $repositories = $githubClient->getRepositories("amphp");
+
+    while (yield $repositories->advance()) {
+        $repository = $repositories->getCurrent();
+        $repository = $repository["full_name"];
+
+        $currentVersion = yield $githubClient->getSubmoduleVersion($repository, "docs/.shared");
+
+        if ($currentVersion !== null && $currentVersion !== $reference) {
+            $stdout->write("{$repository} is not up-to-date, should I update it? [Y/n]: ");
+
+            $answer = trim(yield $stdin->read());
+
+            if ($answer !== "y" && $answer !== "") {
+                exit(0);
+            }
+
+            $master = yield $githubClient->getHead($repository, "master");
+            $baseTree = yield $githubClient->getCommitTree($repository, $master);
+            $baseTree = yield $githubClient->getTree($repository, $baseTree);
+
+            foreach ($baseTree["tree"] as $baseTreeKey => $baseTreeChild) {
+                if ($baseTreeChild["path"] === "docs") {
+                    $docsTree = yield $githubClient->getTree($repository, $baseTreeChild["sha"]);
+
+                    foreach ($docsTree["tree"] as $docsTreeKey => $docsTreeChild) {
+                        if ($docsTreeChild["path"] === ".shared") {
+                            $docsTree["tree"][$docsTreeKey]["sha"] = $reference;
+                        }
+                    }
+
+                    $docsTree = yield $githubClient->createTree($repository, $docsTree["sha"], $docsTree["tree"]);
+                    $baseTree["tree"][$baseTreeKey]["sha"] = $docsTree["sha"];
+                }
+            }
+
+            $newTree = yield $githubClient->createTree($repository, $baseTree["sha"], $baseTree["tree"]);
+
+            $commitMessage = <<<MESSAGE
+Update shared documentation files
+
+This is an automated commit. Please report any issues to https://github.com/amphp/website-tools.
+MESSAGE;
+
+            $commit = yield $githubClient->createCommit($repository, $commitMessage, $newTree["sha"], [$master]);
+            yield $stdout->write("Created {$commit["sha"]} in {$repository}.\r\n");
+
+            $ref = yield $githubClient->updateHead($repository, "master", $commit["sha"]);
+            yield $stdout->write("Updated {$ref["ref"]} in {$repository} to {$commit["sha"]}.\r\n");
+        }
+    }
+});
diff --git a/composer.json b/composer.json
new file mode 100644
index 0000000..71550bf
--- /dev/null
+++ b/composer.json
@@ -0,0 +1,23 @@
+{
+    "name": "amphp/website-tools",
+    "description": "Website tools for amphp.org.",
+    "type": "project",
+    "require": {
+        "amphp/amp": "^2.0",
+        "amphp/artax": "^3.0",
+        "kelunik/oauth-cli": "^1.0",
+        "kelunik/link-header-rfc5988": "^1.0"
+    },
+    "license": "MIT",
+    "authors": [
+        {
+            "name": "Niklas Keller",
+            "email": "me@kelunik.com"
+        }
+    ],
+    "autoload": {
+        "psr-4": {
+            "Amp\\WebsiteTools\\": "src"
+        }
+    }
+}
diff --git a/composer.lock b/composer.lock
new file mode 100644
index 0000000..85286b6
--- /dev/null
+++ b/composer.lock
@@ -0,0 +1,1193 @@
+{
+    "_readme": [
+        "This file locks the dependencies of your project to a known state",
+        "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#composer-lock-the-lock-file",
+        "This file is @generated automatically"
+    ],
+    "content-hash": "f730462ec95a27e19cb87dbd0d1df20a",
+    "packages": [
+        {
+            "name": "amphp/aerys",
+            "version": "v0.6.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/amphp/aerys.git",
+                "reference": "cbf91d62aacb38683aac3cfcb1d72f7955e632e2"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/amphp/aerys/zipball/cbf91d62aacb38683aac3cfcb1d72f7955e632e2",
+                "reference": "cbf91d62aacb38683aac3cfcb1d72f7955e632e2",
+                "shasum": ""
+            },
+            "require": {
+                "amphp/amp": "^2",
+                "amphp/byte-stream": "^1",
+                "amphp/file": "^0.2",
+                "amphp/socket": "^0.10",
+                "league/climate": "^3",
+                "nikic/fast-route": "^1",
+                "php": ">=7",
+                "psr/log": "^1"
+            },
+            "require-dev": {
+                "amphp/artax": "^3",
+                "amphp/phpunit-util": "^1",
+                "friendsofphp/php-cs-fixer": "^2.3@dev",
+                "http2jp/hpack-test-case": "^1",
+                "phpunit/phpunit": "^6"
+            },
+            "bin": [
+                "bin/aerys"
+            ],
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "0.6.0-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Aerys\\": "lib/"
+                },
+                "files": [
+                    "lib/functions.php",
+                    "lib/constants.php",
+                    "lib/Internal/functions.php"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Daniel Lowrey",
+                    "email": "rdlowrey@php.net",
+                    "role": "Creator / Lead Developer"
+                },
+                {
+                    "name": "Bob Weinand",
+                    "role": "Developer / API Coordinator"
+                },
+                {
+                    "name": "Niklas Keller",
+                    "role": "Quality Assurance / Developer"
+                },
+                {
+                    "name": "Aaron Piotrowski",
+                    "email": "aaron@trowski.com"
+                }
+            ],
+            "description": "A non-blocking HTTP/Websocket server",
+            "homepage": "https://github.com/amphp/aerys",
+            "keywords": [
+                "aerys",
+                "amp",
+                "amphp",
+                "async",
+                "http",
+                "non-blocking",
+                "server",
+                "websocket"
+            ],
+            "time": "2017-08-18T08:43:22+00:00"
+        },
+        {
+            "name": "amphp/amp",
+            "version": "v2.0.1",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/amphp/amp.git",
+                "reference": "916cf3119d96ba6d3b5a8c9d9bdd258960400141"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/amphp/amp/zipball/916cf3119d96ba6d3b5a8c9d9bdd258960400141",
+                "reference": "916cf3119d96ba6d3b5a8c9d9bdd258960400141",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=7"
+            },
+            "require-dev": {
+                "amphp/phpunit-util": "^1",
+                "friendsofphp/php-cs-fixer": "^2.3",
+                "phpunit/phpunit": "^6.0.9",
+                "react/promise": "^2"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "2.0.x-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Amp\\": "lib"
+                },
+                "files": [
+                    "lib/functions.php",
+                    "lib/Internal/functions.php"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Bob Weinand",
+                    "email": "bobwei9@hotmail.com"
+                },
+                {
+                    "name": "Niklas Keller",
+                    "email": "me@kelunik.com"
+                },
+                {
+                    "name": "Daniel Lowrey",
+                    "email": "rdlowrey@php.net"
+                },
+                {
+                    "name": "Aaron Piotrowski",
+                    "email": "aaron@trowski.com"
+                }
+            ],
+            "description": "A non-blocking concurrency framework for PHP applications.",
+            "homepage": "http://amphp.org/amp",
+            "keywords": [
+                "async",
+                "asynchronous",
+                "awaitable",
+                "concurrency",
+                "event",
+                "event-loop",
+                "future",
+                "non-blocking",
+                "promise"
+            ],
+            "time": "2017-07-09T12:20:40+00:00"
+        },
+        {
+            "name": "amphp/artax",
+            "version": "v3.0.4",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/amphp/artax.git",
+                "reference": "48008dcfd6e7376d5631a6c55bdf01ff94878537"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/amphp/artax/zipball/48008dcfd6e7376d5631a6c55bdf01ff94878537",
+                "reference": "48008dcfd6e7376d5631a6c55bdf01ff94878537",
+                "shasum": ""
+            },
+            "require": {
+                "amphp/amp": "^2",
+                "amphp/file": "^0.2",
+                "amphp/socket": "^0.10",
+                "amphp/uri": "^0.1",
+                "kelunik/certificate": "^1.1",
+                "php": ">=7.0"
+            },
+            "require-dev": {
+                "amphp/phpunit-util": "^1",
+                "friendsofphp/php-cs-fixer": "^2.3",
+                "phpunit/phpunit": "^6"
+            },
+            "type": "library",
+            "autoload": {
+                "psr-4": {
+                    "Amp\\Artax\\": "lib"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Niklas Keller",
+                    "email": "me@kelunik.com"
+                },
+                {
+                    "name": "Daniel Lowrey",
+                    "email": "rdlowrey@gmail.com"
+                }
+            ],
+            "description": "Asynchronous parallel HTTP/1.1 client built on the Amp concurrency framework",
+            "homepage": "https://github.com/amphp/artax",
+            "keywords": [
+                "async",
+                "client",
+                "http",
+                "non-blocking",
+                "parallel",
+                "rest"
+            ],
+            "time": "2017-07-14T13:01:08+00:00"
+        },
+        {
+            "name": "amphp/byte-stream",
+            "version": "v1.1.3",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/amphp/byte-stream.git",
+                "reference": "fdcf400f19af26d06d183127d7cce57b24c574cf"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/amphp/byte-stream/zipball/fdcf400f19af26d06d183127d7cce57b24c574cf",
+                "reference": "fdcf400f19af26d06d183127d7cce57b24c574cf",
+                "shasum": ""
+            },
+            "require": {
+                "amphp/amp": "^2"
+            },
+            "require-dev": {
+                "amphp/phpunit-util": "^1",
+                "friendsofphp/php-cs-fixer": "^2.3",
+                "phpunit/phpunit": "^6"
+            },
+            "type": "library",
+            "autoload": {
+                "psr-4": {
+                    "Amp\\ByteStream\\": "lib"
+                },
+                "files": [
+                    "lib/functions.php"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Niklas Keller",
+                    "email": "me@kelunik.com"
+                },
+                {
+                    "name": "Aaron Piotrowski",
+                    "email": "aaron@trowski.com"
+                }
+            ],
+            "description": "A stream abstraction to make working with non-blocking I/O simple.",
+            "homepage": "http://amphp.org/byte-stream",
+            "keywords": [
+                "amp",
+                "amphp",
+                "async",
+                "io",
+                "non-blocking",
+                "stream"
+            ],
+            "time": "2017-09-15T05:17:42+00:00"
+        },
+        {
+            "name": "amphp/cache",
+            "version": "v1.1.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/amphp/cache.git",
+                "reference": "d6ab81ce35019b0fd84ca6d665fd4817bfd11701"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/amphp/cache/zipball/d6ab81ce35019b0fd84ca6d665fd4817bfd11701",
+                "reference": "d6ab81ce35019b0fd84ca6d665fd4817bfd11701",
+                "shasum": ""
+            },
+            "require": {
+                "amphp/amp": "^2"
+            },
+            "require-dev": {
+                "amphp/phpunit-util": "^1",
+                "friendsofphp/php-cs-fixer": "^2.3",
+                "phpunit/phpunit": "^6"
+            },
+            "type": "library",
+            "autoload": {
+                "psr-4": {
+                    "Amp\\Cache\\": "lib"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Niklas Keller",
+                    "email": "me@kelunik.com"
+                },
+                {
+                    "name": "Daniel Lowrey",
+                    "email": "rdlowrey@php.net"
+                }
+            ],
+            "description": "A promise-aware caching API for Amp.",
+            "homepage": "https://github.com/amphp/cache",
+            "time": "2017-06-24T09:51:10+00:00"
+        },
+        {
+            "name": "amphp/dns",
+            "version": "v0.9.8",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/amphp/dns.git",
+                "reference": "1a41089d84675bbeed3b5c655ffccd3318a21f37"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/amphp/dns/zipball/1a41089d84675bbeed3b5c655ffccd3318a21f37",
+                "reference": "1a41089d84675bbeed3b5c655ffccd3318a21f37",
+                "shasum": ""
+            },
+            "require": {
+                "amphp/amp": "^2",
+                "amphp/byte-stream": "^1.1",
+                "amphp/cache": "^1",
+                "amphp/file": "^0.2",
+                "amphp/parser": "^1",
+                "amphp/uri": "^0.1",
+                "amphp/windows-registry": "^0.3",
+                "daverandom/libdns": "^1",
+                "php": ">=7.0"
+            },
+            "require-dev": {
+                "amphp/phpunit-util": "^1",
+                "friendsofphp/php-cs-fixer": "^2.3",
+                "phpunit/phpunit": "^6"
+            },
+            "type": "library",
+            "autoload": {
+                "psr-4": {
+                    "Amp\\Dns\\": "lib"
+                },
+                "files": [
+                    "lib/functions.php"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Bob Weinand",
+                    "email": "bobwei9@hotmail.com"
+                },
+                {
+                    "name": "Niklas Keller",
+                    "email": "me@kelunik.com"
+                },
+                {
+                    "name": "Daniel Lowrey",
+                    "email": "rdlowrey@php.net"
+                },
+                {
+                    "name": "Chris Wright",
+                    "email": "addr@daverandom.com"
+                },
+                {
+                    "name": "Aaron Piotrowski",
+                    "email": "aaron@trowski.com"
+                }
+            ],
+            "description": "Async DNS resolution for Amp.",
+            "homepage": "https://github.com/amphp/dns",
+            "keywords": [
+                "amp",
+                "amphp",
+                "async",
+                "client",
+                "dns",
+                "resolve"
+            ],
+            "time": "2017-09-12T15:08:38+00:00"
+        },
+        {
+            "name": "amphp/file",
+            "version": "v0.2.4",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/amphp/file.git",
+                "reference": "577bcc1f92252a795f9871e183b0caef975c9635"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/amphp/file/zipball/577bcc1f92252a795f9871e183b0caef975c9635",
+                "reference": "577bcc1f92252a795f9871e183b0caef975c9635",
+                "shasum": ""
+            },
+            "require": {
+                "amphp/amp": "^2",
+                "amphp/byte-stream": "^1",
+                "amphp/parallel": "^0.1.8"
+            },
+            "require-dev": {
+                "amphp/phpunit-util": "^1",
+                "friendsofphp/php-cs-fixer": "^2.3",
+                "phpunit/phpunit": "^6"
+            },
+            "type": "library",
+            "autoload": {
+                "psr-4": {
+                    "Amp\\File\\": "lib"
+                },
+                "files": [
+                    "lib/functions.php"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Niklas Keller",
+                    "email": "me@kelunik.com"
+                },
+                {
+                    "name": "Daniel Lowrey",
+                    "email": "rdlowrey@php.net"
+                },
+                {
+                    "name": "Aaron Piotrowski",
+                    "email": "aaron@trowski.com"
+                }
+            ],
+            "description": "Allows non-blocking access to the filesystem for Amp.",
+            "homepage": "https://github.com/amphp/file",
+            "keywords": [
+                "amp",
+                "amphp",
+                "async",
+                "disk",
+                "file",
+                "filesystem",
+                "io",
+                "non-blocking",
+                "static"
+            ],
+            "time": "2017-07-21T06:32:23+00:00"
+        },
+        {
+            "name": "amphp/parallel",
+            "version": "v0.1.8",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/amphp/parallel.git",
+                "reference": "25b9a2a75c4a6ba4815775267822066abab1054a"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/amphp/parallel/zipball/25b9a2a75c4a6ba4815775267822066abab1054a",
+                "reference": "25b9a2a75c4a6ba4815775267822066abab1054a",
+                "shasum": ""
+            },
+            "require": {
+                "amphp/amp": "^2",
+                "amphp/byte-stream": "^1.1",
+                "amphp/parser": "^1",
+                "amphp/process": "^0.2"
+            },
+            "require-dev": {
+                "amphp/phpunit-util": "^1",
+                "friendsofphp/php-cs-fixer": "^2.3",
+                "phpunit/phpunit": "^6"
+            },
+            "suggest": {
+                "ext-pcntl": "Required for fork contexts",
+                "ext-pthreads": "Required for thread contexts",
+                "ext-sysvsem": "Required for fork synchronization",
+                "ext-sysvshm": "Required for fork contexts"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "0.1.x-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Amp\\Parallel\\": "lib"
+                },
+                "files": [
+                    "lib/Worker/functions.php"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Stephen Coakley",
+                    "email": "me@stephencoakley.com"
+                },
+                {
+                    "name": "Aaron Piotrowski",
+                    "email": "aaron@trowski.com"
+                }
+            ],
+            "description": "Parallel processing component for Amp.",
+            "homepage": "https://github.com/amphp/parallel",
+            "keywords": [
+                "async",
+                "asynchronous",
+                "concurrent",
+                "multi-processing",
+                "multi-threading"
+            ],
+            "time": "2017-07-18T03:59:56+00:00"
+        },
+        {
+            "name": "amphp/parser",
+            "version": "v1.0.0",
+            "source": {
+                "type": "git",
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+            "license": [
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+                },
+                {
+                    "name": "Aaron Piotrowski",
+                    "email": "aaron@trowski.com"
+                }
+            ],
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+            "homepage": "https://github.com/amphp/process",
+            "time": "2017-07-18T03:37:19+00:00"
+        },
+        {
+            "name": "amphp/socket",
+            "version": "v0.10.2",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/amphp/socket.git",
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+                "php": ">=7.0"
+            },
+            "require-dev": {
+                "amphp/phpunit-util": "^1",
+                "friendsofphp/php-cs-fixer": "^2.3",
+                "phpunit/phpunit": "^6"
+            },
+            "type": "library",
+            "autoload": {
+                "psr-4": {
+                    "Amp\\Socket\\": "lib"
+                },
+                "files": [
+                    "lib/functions.php",
+                    "lib/Internal/functions.php"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
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+                    "email": "me@kelunik.com"
+                },
+                {
+                    "name": "Daniel Lowrey",
+                    "email": "rdlowrey@gmail.com"
+                },
+                {
+                    "name": "Aaron Piotrowski",
+                    "email": "aaron@trowski.com"
+                }
+            ],
+            "description": "Async socket connection / server tools for Amp.",
+            "homepage": "https://github.com/amphp/socket",
+            "keywords": [
+                "amp",
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+        },
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+                },
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+                ]
+            },
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+            "license": [
+                "MIT"
+            ],
+            "authors": [
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+                    "email": "me@kelunik.com"
+                },
+                {
+                    "name": "Daniel Lowrey"
+                }
+            ],
+            "description": "Uri Parser and Resolver.",
+            "homepage": "https://github.com/amphp/uri",
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+        },
+        {
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+            "version": "v0.3.0",
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+                "url": "https://github.com/amphp/windows-registry.git",
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+                }
+            },
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+        },
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+                "php": "^5.4 | ^7.0"
+            },
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+            },
+            "type": "library",
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+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Niklas Keller",
+                    "email": "me@kelunik.com"
+                }
+            ],
+            "description": "Access certificate details and transform between different formats.",
+            "keywords": [
+                "DER",
+                "certificate",
+                "certificates",
+                "openssl",
+                "pem",
+                "x509"
+            ],
+            "time": "2017-07-04T19:37:30+00:00"
+        },
+        {
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+            "version": "v1.0.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/kelunik/link-header-rfc5988.git",
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+            },
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+                    "Kelunik\\LinkHeaderRfc5988\\": "src"
+                },
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+                    "src/functions.php"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
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+                "MIT"
+            ],
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+                {
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+                    "email": "me@kelunik.com"
+                }
+            ],
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+        },
+        {
+            "name": "kelunik/oauth",
+            "version": "v0.1.2",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/kelunik/oauth.git",
+                "reference": "4fcdf905b96aff35ac89bc9a6b1d240e7c7a37d5"
+            },
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+                "shasum": ""
+            },
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+            },
+            "require-dev": {
+                "friendsofphp/php-cs-fixer": "^2.3"
+            },
+            "type": "library",
+            "autoload": {
+                "psr-4": {
+                    "Kelunik\\OAuth\\": "src"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Niklas Keller",
+                    "email": "me@kelunik.com"
+                }
+            ],
+            "time": "2017-09-16T08:58:04+00:00"
+        },
+        {
+            "name": "kelunik/oauth-cli",
+            "version": "v1.0.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/kelunik/oauth-cli.git",
+                "reference": "40f091562b9079a88ed33e042498859f7ca6415a"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/kelunik/oauth-cli/zipball/40f091562b9079a88ed33e042498859f7ca6415a",
+                "reference": "40f091562b9079a88ed33e042498859f7ca6415a",
+                "shasum": ""
+            },
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+                "amphp/artax": "^3.0",
+                "kelunik/oauth": "^0.1.1"
+            },
+            "type": "library",
+            "autoload": {
+                "files": [
+                    "src/functions.php"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Niklas Keller",
+                    "email": "me@kelunik.com"
+                }
+            ],
+            "description": "Allows using OAuth as login method on CLI.",
+            "time": "2017-09-15T07:38:26+00:00"
+        },
+        {
+            "name": "league/climate",
+            "version": "3.2.1",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/thephpleague/climate.git",
+                "reference": "b103fc8faa3780c802cc507d5f0ff534ecc94fb5"
+            },
+            "dist": {
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+                "url": "https://api.github.com/repos/thephpleague/climate/zipball/b103fc8faa3780c802cc507d5f0ff534ecc94fb5",
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+            },
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+            },
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+                "mockery/mockery": "~0.9",
+                "phpunit/phpunit": "~4.6"
+            },
+            "type": "library",
+            "autoload": {
+                "psr-4": {
+                    "League\\CLImate\\": "src/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Joe Tannenbaum",
+                    "email": "hey@joe.codes",
+                    "homepage": "http://joe.codes/",
+                    "role": "Developer"
+                }
+            ],
+            "description": "PHP's best friend for the terminal. CLImate allows you to easily output colored text, special formats, and more.",
+            "keywords": [
+                "cli",
+                "colors",
+                "command",
+                "php",
+                "terminal"
+            ],
+            "time": "2016-04-04T20:24:59+00:00"
+        },
+        {
+            "name": "nikic/fast-route",
+            "version": "v1.2.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/nikic/FastRoute.git",
+                "reference": "b5f95749071c82a8e0f58586987627054400cdf6"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/nikic/FastRoute/zipball/b5f95749071c82a8e0f58586987627054400cdf6",
+                "reference": "b5f95749071c82a8e0f58586987627054400cdf6",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=5.4.0"
+            },
+            "type": "library",
+            "autoload": {
+                "psr-4": {
+                    "FastRoute\\": "src/"
+                },
+                "files": [
+                    "src/functions.php"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "BSD-3-Clause"
+            ],
+            "authors": [
+                {
+                    "name": "Nikita Popov",
+                    "email": "nikic@php.net"
+                }
+            ],
+            "description": "Fast request router for PHP",
+            "keywords": [
+                "router",
+                "routing"
+            ],
+            "time": "2017-01-19T11:35:12+00:00"
+        },
+        {
+            "name": "psr/log",
+            "version": "1.0.2",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/php-fig/log.git",
+                "reference": "4ebe3a8bf773a19edfe0a84b6585ba3d401b724d"
+            },
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+                "type": "zip",
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+                "reference": "4ebe3a8bf773a19edfe0a84b6585ba3d401b724d",
+                "shasum": ""
+            },
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+                "php": ">=5.3.0"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "1.0.x-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Psr\\Log\\": "Psr/Log/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "PHP-FIG",
+                    "homepage": "http://www.php-fig.org/"
+                }
+            ],
+            "description": "Common interface for logging libraries",
+            "homepage": "https://github.com/php-fig/log",
+            "keywords": [
+                "log",
+                "psr",
+                "psr-3"
+            ],
+            "time": "2016-10-10T12:19:37+00:00"
+        },
+        {
+            "name": "seld/cli-prompt",
+            "version": "1.0.3",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/Seldaek/cli-prompt.git",
+                "reference": "a19a7376a4689d4d94cab66ab4f3c816019ba8dd"
+            },
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+                "url": "https://api.github.com/repos/Seldaek/cli-prompt/zipball/a19a7376a4689d4d94cab66ab4f3c816019ba8dd",
+                "reference": "a19a7376a4689d4d94cab66ab4f3c816019ba8dd",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=5.3"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "1.x-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Seld\\CliPrompt\\": "src/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Jordi Boggiano",
+                    "email": "j.boggiano@seld.be"
+                }
+            ],
+            "description": "Allows you to prompt for user input on the command line, and optionally hide the characters they type",
+            "keywords": [
+                "cli",
+                "console",
+                "hidden",
+                "input",
+                "prompt"
+            ],
+            "time": "2017-03-18T11:32:45+00:00"
+        }
+    ],
+    "packages-dev": [],
+    "aliases": [],
+    "minimum-stability": "stable",
+    "stability-flags": [],
+    "prefer-stable": false,
+    "prefer-lowest": false,
+    "platform": [],
+    "platform-dev": []
+}
diff --git a/src/GitHubClient.php b/src/GitHubClient.php
new file mode 100644
index 0000000..84f1919
--- /dev/null
+++ b/src/GitHubClient.php
@@ -0,0 +1,182 @@
+<?php
+
+namespace Amp\WebsiteTools;
+
+use Amp\Artax\Client;
+use Amp\Artax\DefaultClient;
+use Amp\Artax\Request;
+use Amp\Artax\Response;
+use Amp\Iterator;
+use Amp\Producer;
+use Amp\Promise;
+use function Amp\call;
+use function Kelunik\LinkHeaderRfc5988\parseLinks;
+
+class GitHubClient {
+    private $accessToken;
+    private $client;
+
+    public function __construct(string $accessToken, Client $client = null) {
+        $this->accessToken = $accessToken;
+        $this->client = $client ?? new DefaultClient;
+    }
+
+    public function get(string $uri): Promise {
+        return call(function () use ($uri) {
+            /** @var Response $response */
+            $response = yield $this->client->request(
+                (new Request($uri))->withHeader("authorization", "token {$this->accessToken}")
+            );
+
+            $json = \json_decode(yield $response->getBody(), true);
+
+            if ($response->getStatus() !== 200) {
+                throw new \Exception("Request failed ($uri): " . $json["message"] . " (" . $json["documentation_url"] . ")");
+            }
+
+            return $json;
+        });
+    }
+
+    public function post(string $uri, array $json): Promise {
+        return call(function () use ($uri, $json) {
+            $body = json_encode($json);
+
+            /** @var Response $response */
+            $response = yield $this->client->request(
+                (new Request($uri, "POST"))->withHeader("authorization", "token {$this->accessToken}")
+                    ->withBody($body)
+            );
+
+            $json = \json_decode(yield $response->getBody(), true);
+
+            if ((int) ($response->getStatus() / 100) !== 2) {
+                throw new \Exception("Request failed (" . $response->getStatus() . "): " . yield $response->getBody());
+            }
+
+            return $json;
+        });
+    }
+
+    public function patch(string $uri, array $json): Promise {
+        return call(function () use ($uri, $json) {
+            $body = json_encode($json);
+
+            /** @var Response $response */
+            $response = yield $this->client->request(
+                (new Request($uri, "PATCH"))->withHeader("authorization", "token {$this->accessToken}")
+                    ->withBody($body)
+            );
+
+            $json = \json_decode(yield $response->getBody(), true);
+
+            if ((int) ($response->getStatus() / 100) !== 2) {
+                throw new \Exception("Request failed (" . $response->getStatus() . "): " . yield $response->getBody());
+            }
+
+            return $json;
+        });
+    }
+
+    public function getHead(string $repository, string $branch): Promise {
+        return call(function () use ($repository, $branch) {
+            $json = yield $this->get("https://api.github.com/repos/{$repository}/git/refs/heads/{$branch}");
+
+            return $json["object"]["sha"];
+        });
+    }
+
+    public function getSubmoduleVersion(string $repository, string $path): Promise {
+        return call(function () use ($repository, $path) {
+            try {
+                $json = yield $this->get("https://api.github.com/repos/{$repository}/contents/{$path}");
+
+                return $json["sha"];
+            } catch (\Exception $e) {
+                return null;
+            }
+        });
+    }
+
+    public function getCommitTree($repository, $sha) {
+        return call(function () use ($repository, $sha) {
+            $json = yield $this->get("https://api.github.com/repos/{$repository}/git/commits/{$sha}");
+
+            return $json["tree"]["sha"];
+        });
+    }
+
+    public function getTree($repository, $baseTree) {
+        return call(function () use ($repository, $baseTree) {
+            $json = yield $this->get("https://api.github.com/repos/{$repository}/git/trees/{$baseTree}");
+
+            if ($json["truncated"] === true) {
+                throw new \Exception("Got a truncated tree: {$json["sha"]}");
+            }
+
+            return $json;
+        });
+    }
+
+    public function createTree($repository, $baseTree, $tree) {
+        return call(function () use ($repository, $baseTree, $tree) {
+            $json = yield $this->post("https://api.github.com/repos/{$repository}/git/trees", [
+                "base_tree" => $baseTree,
+                "tree" => $tree,
+            ]);
+
+            return $json;
+        });
+    }
+
+    public function createCommit(string $repository, string $message, string $tree, array $parents) {
+        return call(function () use ($repository, $message, $tree, $parents) {
+            $json = yield $this->post("https://api.github.com/repos/{$repository}/git/commits", [
+                "message" => $message,
+                "tree" => $tree,
+                "parents" => $parents,
+            ]);
+
+            return $json;
+        });
+    }
+
+    public function updateHead($repository, $branch, $sha) {
+        return call(function () use ($repository, $branch, $sha) {
+            $json = yield $this->patch("https://api.github.com/repos/{$repository}/git/refs/heads/{$branch}", [
+                "sha" => $sha,
+                "force" => false,
+            ]);
+
+            return $json;
+        });
+    }
+
+    public function getRepositories(string $organization): Iterator {
+        return new Producer(function ($emit) use ($organization) {
+            $uri = "https://api.github.com/orgs/{$organization}/repos";
+
+            do {
+                /** @var Response $response */
+                $response = yield $this->client->request(
+                    (new Request($uri))->withHeader("authorization", "token {$this->accessToken}")
+                );
+
+                $json = \json_decode(yield $response->getBody(), true);
+
+                if ($response->getStatus() !== 200) {
+                    throw new \Exception("Request failed ($uri): " . $json["message"] . " (" . $json["documentation_url"] . ")");
+                }
+
+                foreach ($json as $repository) {
+                    yield $emit($repository);
+                }
+
+                $linkHeader = $response->getHeader("link");
+                $links = parseLinks($linkHeader ?? "");
+
+                $uri = ($link = $links->getByRel("next")) ? $link->getUri() : null;
+            } while ($uri);
+        });
+    }
+}
\ No newline at end of file