Added a bunch of developer documentation

docs/index.rst

@@ -1,12 +1,39 @@
-InvenTree's Django Documentation
+InvenTree Source Documentation
 ================================
 
-This documentation is auto-generated from the `InvenTree codebase <https://github.com/InvenTree/InvenTree>`_
-
 .. toctree::
    :titlesonly:
    :maxdepth: 2
-   :caption: Contents:
+   :caption: Index
+   :hidden:
 
-   InvenTree Modules <introduction>
-   API Reference<reference>
+   Getting Started<start>
+   Modal Forms<forms>
+   Tables<tables>
+   REST API<rest>
+   Backup and Restore<backup>
+   InvenTree Modules <modules>
+   Module Reference<reference>
+
+The documentation found here is provided to be useful for developers working on the InvenTree codebase. User documentation can be found on the `InvenTree website <https://inventree.github.io>`_.
+
+Documentation for the Python modules is auto-generated from the `InvenTree codebase <https://github.com/InvenTree/InvenTree>`_.
+
+Code Structure
+--------------
+
+**Backend**
+
+InvenTree is developed using the `django web framework <https://www.djangoproject.com/>`_, a powerful toolkit for making web applications in Python.
+
+The database management code and business logic is written in Python 3. Core functionality is separated into individual modules (or *apps* using the django nomenclature).
+
+Each *app* is located in a separate directory under InvenTree. Each *app* contains python modules named according to the standard django configuration.
+
+**Frontend**
+
+The web frontend rendered using a mixture of technologies.
+
+Base HTML code is rendered using the `django templating language <https://docs.djangoproject.com/en/2.2/topics/templates/>`_ which provides low-level access to the underlying database models.
+
+jQuery is also used to implement front-end logic, and desponse to user input. A REST API is provided to facilitate client-server communication.