docs: add documentation on the manifest

Signed-off-by: Vincenzo Palazzo <[email protected]>

docs/docs-book/src/support-coffee.md

@@ -1,5 +1,43 @@
 # How to support?
 
+Core Lightning support many different ways to write a plugin, and if this is bad or good
+will not be discussed in this section.
+However, we must have a way to install automatically all the plugins that the ecosystem supports.
+
+With Coffee, we choose to give this freedom to the developers of the plugin, in fact, coffee uses a
+manifest where it is possible to specify the install script and the runnable file/binary file.
+
 ## Add a Manifest file
 
-Add a manifest in the root directory called `coffee.yml` or `coffee.yaml`.
+The coffee manifest is a yaml file with the name `coffee.yml` or `coffee.yaml`, where it is possible
+specify the install script an other meta information.
+
+Coffee will heavily search this file in the root directory of the plugin, and it is not so different
+from what the other languages like nodejs, go, rust does.
+
+An example of the coffee manifest that will install a Kotlin plugin is the following one:
+
+```yaml
+---
+plugin:
+  name: btcli4j
+  version: 0.0.1
+  lang: java
+  install: |
+    sh -C ./gradlew createRunnableScript
+  main: btcli4j-gen.sh
+```
+
+Where it is possible to specify the following options:
+
+- `name`: the official name of the plugin, that Coffee will referer to during the installation process;
+- `version`: the version of the plugin, that currently is not used;
+- `lang`: the language of the plugin, used to try to install a plugin when the `install` script is not specified;
+- `install`: a custom install script used by Coffee to compile the plugin;
+- `main`: the binary or runnable file that core lightning needs to run.
+
+In the future, the coffee will be also able to install `binary` other than a `plugin`, so coffee will be installed with coffee
+itself. With some craziness will be also possible to manage core lightning itself.
+
+Please if you feel that additional meta information needs to be specified open an issue 
+https://github.com/coffee-tools/coffee/issues