Update index.rst to restructure

Issue #1943

Author: DennisClark

docs/source/index.rst

@@ -1,58 +1,78 @@
-Welcome to VulnerableCode!
-=============================
+VulnerableCode Documentation
+============================
 
-*VulnerableCode* provides an open database of software packages that are affected
-by known security vulnerabilities aka. *"vulnerable packages"*.
+*VulnerableCode* provides a Web UI and API to access a database of known software package
+vulnerabilities with comprehensive information from upstream and downstream public
+sources including packages affected by a vulnerability and packages that fix a
+vulnerability.
 
-VulnerableCode is also a free and open source software (FOSS) project that
-provides the tools to build this open database. The tools handle collecting,
-aggregating and correlating these vulnerabilities and relating them to a correct
-package version. Our project also supports a public cloud instance of this
-database - VulnerableCode.io.
+There is a `public VulnerableCode database <https://public.vulnerablecode.io/>`_
+and the project also provides the tools to build your own instance of the database.
 
-In this documentation you will find information on:
+Documentation overview
+~~~~~~~~~~~~~~~~~~~~~~
 
-- An overview of VulnerableCode and what you can do with it
-- Installation instructions
-- How to make technical contributions to the project and the community
+The overview below outlines how the documentation is structured
+to help you know where to look for certain things.
 
-.. toctree::
-    :maxdepth: 2
-    :caption: Getting Started
+.. rst-class:: clearfix row
 
-    introduction
-    user-interface
-    installation
-    api
-    api-admin
-    contributing
-    faq
-    misc
+.. rst-class:: column column2 top-left
 
-.. toctree::
-    :maxdepth: 2
-    :caption: Tutorial
+Getting started
+~~~~~~~~~~~~~~~~~~~~~~
 
-    tutorial_add_importer_pipeline
-    tutorial_add_improver_pipeline
+Start here if you are new to VulnerableCode.
 
+- :ref:`introduction`
+- :ref:`user_interface`
+- :ref:`installation`
+- :ref:`api`
+- :ref:`api-admin`
+- :ref:`contributing`
 
-.. toctree::
-    :maxdepth: 2
-    :caption: Reference Documentation
+.. rst-class:: column column2 top-right
 
-    reference_importer_overview
-    reference_improver_overview
-    reference_framework_overview
-    reference_model_overview
-    command-line-interface
-    importers_link
+Tutorials
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-.. toctree::
-   :maxdepth: 1
-   :caption: Summer of Codes
+Learn via practical step-by-step guides.
+
+- :ref:`tutorial_add_importer_pipeline`
+- :ref:`tutorial_add_improver_pipeline`
+
+.. rst-class:: column column2 bottom-left
+
+Reference Docs
+~~~~~~~~~~~~~~~~~~
+
+Reference documentation for VulnerableCode features and customizations.
+
+- :ref:`reference_importer_overview`
+- :ref:`reference_improver_overview`
+- :ref:`reference_framework_overview`
+- :ref:`reference_model_overview`
+- :ref:`command_line_interface`
+- :ref:`importers_link`
+
+.. rst-class:: column column2 bottom-right
+
+Explanations
+~~~~~~~~~~~~~~~~~~
+
+Consult the reference to understand VulnerableCode concepts.
+
+.. rst-class:: row clearfix
+
+Misc
+~~~~~~~~~~~~~~~
+
+- :ref:`faq`
+- :ref:`misc`
+- :ref:`soc_gsoc21`
+
+.. include:: improve-docs.rst
 
-   soc_gsoc21
 
 Indices and tables
 ==================