add technical description to welcome page

docs/index.rst

@@ -5,21 +5,27 @@
 Welcome
 =======
 
-Deis is an open source PaaS that makes it easy to deploy LXC Containers and 
-Chef Nodes used to host applications, databases, middleware and other services.
-Deis leverages Chef, Docker and Heroku Buildpacks to provide a private PaaS 
-that is lightweight and flexible.
+Deis is a Django/Celery API server, Python CLI and set of
+`Chef cookbooks`_ that combine to provide a Heroku-inspired application
+platform for public and private clouds. Your PaaS. Your Rules.
+
+Deis makes it easy to deploy and scale LXC containers and Chef nodes
+used to host applications, databases, middleware and other services.
+Deis leverages Chef, Docker and Heroku Buildpacks to provide a private
+PaaS that is lightweight and flexible.
 
 .. image:: _static/img/deis-graphic.png
 
 If you are new to Deis, you should start with :ref:`Concepts`.
 Once you've completed :ref:`installation` of your private Deis controller,
-you should explore :ref:`usage` of the command-line client 
+you should explore :ref:`usage` of the command-line client
 which is elaborated on in the :ref:`tutorial`.
 
 Want to learn about Deis internals?  You'll find complete API documentation
 in the :ref:`client` and :ref:`server` sections.
 
 Interested in contributing to the Deis project?  Check out our
-:ref:`Contributor Overview <contributor>` and 
+:ref:`Contributor Overview <contributor>` and
 :ref:`devsetup` instructions.
+
+.. _`Chef cookbooks`: https://github.com/opdemand/deis-cookbook