Added basic custom modules docs

docs/custom_modules.rst

@@ -0,0 +1,57 @@
+Custom Modules
+==============
+
+Invoice Ninja support customs modules using https://github.com/nWidart/laravel-modules
+
+Install Module
+""""""""""""""
+
+To install a module run:
+
+.. code-block:: ruby
+
+    php artisan module:install <vendor/module> --type=github
+
+For example:
+
+.. code-block:: ruby
+
+    php artisan module:install invoiceninja/sprockets --type=github
+
+You can check the current module status with:
+
+.. code-block:: ruby
+
+    php artisan module:list
+
+
+Create Module
+"""""""""""""
+
+Run the following command to create a module:
+
+.. code-block:: ruby
+
+    php artisan module:make <module>
+
+.. Note:: To use the standard app layout change the top of Modules/<module>/Resources/views/index.blade.php to ``@extends('header')``
+
+.. Tip:: You can specify the module icon by setting a value from http://fontawesome.io/icons/ for "icon" in modules.json.
+
+Share Module
+""""""""""""
+
+To share your module create a new project on GitHub and then commit the code:
+
+.. code-block:: ruby
+
+    cd Modules/<module>
+    git init
+    git add .
+    git commit -m "Initial commit"
+    git remote add origin git@github.com:<vendor/module>.git
+    git push -f origin master
+
+.. Tip:: Add ``"type": "invoiceninja-module"`` to the composer.json file to help people find your module.
+
+Finally, submit the project to https://packagist.org. 

docs/index.rst

@@ -36,11 +36,12 @@ Want to find out everything there is to know about how to use your Invoice Ninja
    data_visualizations
    api_tokens
    user_management
-   
+
 .. _self_host:
 
 .. toctree::
    :maxdepth: 1
    :caption: Self Host
-   
+
+   custom_modules
    iphone_app