update readme

Author: ciur

README.rst

@@ -1,10 +1,17 @@
 
-Papermerge - Core
-###################
+Papermerge Core
+################
 
-Papermerge Core contains essential functionality shared among different flavors of
-Papermerge Document Management System (DMS).
+Papermerge Core reusable Django apps are the heart of Papermerge project. It is
+(re)used across different flavors of Papermerge Document Management System
+(DMS). It contains the core functionality, models and API used throughout
+Papermerge ecosystem.
 
+Technically speaking, it contains following django apps:
+
+* papermerge.core - the epicenter of papermerge project which defines main models
+* papermerge.contrib.admin - user interface is defined here
+* papermerge.search - unified search API
 
 What is Papermerge?
 ~~~~~~~~~~~~~~~~~~~
@@ -19,3 +26,5 @@ index it and make it searchable. You will be able to quickly find any
 (scanned!) document using full text search capabilities.
 
 Papermerge is perfect tool to manage PDF, JPEG, TIFF and PNG formats.
+
+.. figure:: img/screenshot.png