Added call to donate after npm install (optional)

package.json

@@ -18,7 +18,8 @@
     "dev": "babel -w src --out-dir dist --ignore __tests__",
     "test": "xo && ava",
     "pretest": "npm run build",
-    "semantic-release": "semantic-release"
+    "semantic-release": "semantic-release",
+    "postinstall": "opencollective postinstall"
   },
   "main": "dist/index.js",
   "files": [
@@ -43,6 +44,7 @@
     "ink-spinner": "^1.0.0",
     "ink-text-input": "^1.1.1",
     "meow": "^4.0.0",
+    "opencollective": "^1.0.3",
     "term-size": "^1.2.0",
     "update-notifier": "^2.3.0",
     "yargs": "^11.0.0"
@@ -82,5 +84,10 @@
   "repository": {
     "type": "git",
     "url": "https://github.com/maticzav/emma-cli.git"
+  },
+  "collective": {
+    "type": "opencollective",
+    "url": "https://opencollective.com/emma-cli",
+    "logo": "https://opencollective.com/emma-cli/logo.txt"
   }
-}
+}