Adding the documentation section on how to setup the post-install for…

… a given plugin.

docs/source/development/plugin_registry.rst

@@ -21,7 +21,8 @@ To include your plugin in the registry, follow these steps:
         author: "Alice Doe"
         github: "https://github.com/alicedoe/aiidalab-qe-xyz"
         documentation: "https://aiidalab-qe-xyz.readthedocs.io/"
-        pip: "aiidalab-qe-xyz"
+        pip: "aiidalab-qe-xyz==version-of-the-code"
+        post-install: "post-install-command"
 
 3. Submit a Pull Request. Direct it to `this repository's Pull Requests section <https://github.com/aiidalab/aiidalab-qe/pulls>`_.
 
@@ -37,10 +38,19 @@ Plugin Entry Requirements
 
 - **github:** If provided, this should be the URL to the plugin's GitHub homepage.
 
-At least one of ``github`` or ``pip`` is required.
+At least one of ``github`` or ``pip`` is required. ``pip`` installation will be preferred if both are provided, and "==version-of-the-code" can be omitted (but strongly suggested, to ensure compatiblity).
 
 - **pip:** The PyPI package name for your plugin, useful for installation via pip. Example: ``aiida-quantum``.
 - **documentation:** The URL to your plugin's online documentation, such as ReadTheDocs.
 - **author:** The developer of the plugin.
+- **post-install:** a post install Command Line Interface (CLI) command which should be defined inside your plugin if you needs it. For example in the ``aiidalab-qe-vibroscopy`` plugin, we automatically setup the phonopy code via this command. See below for more explanations.
 
-By following these guidelines, you can ensure your plugin is correctly listed and accessible within the AiiDAlab Quantum ESPRESSO app, facilitating its discovery and use by the community.
+How to define a post install command in your plugin
+---------------------------------------------------------------------
+
+If you need to run a post-install command, you can define it in the CLI of your package, meant to be run as ``package-name post-install-command``.  
+You can define the CLI  in the ``__main__.py``  (in your source folder) and ``pyproject.toml`` files. Have a look at the  ``aiidalab-qe-vibroscopy`` plugin for an example on how to do this. 
+There, the automatic setup the phonopy code in the AiiDA database is implemented.
+The command will be then triggered after the installation of the plugin (only) from the plugin list page of the Quantum ESPRESSO app. 
+
+By following these guidelines, you can ensure your plugin is correctly listed and accessible within the AiiDAlab Quantum ESPRESSO app, facilitating its discovery and use by the community.