set headlines for "demo" and "documentation"

README.md

@@ -3,11 +3,17 @@ SonataAdminBundle - The missing Symfony2 Admin Generator
 
 [![Build Status](https://secure.travis-ci.org/sonata-project/SonataAdminBundle.png?branch=master)](http://travis-ci.org/sonata-project/SonataAdminBundle)
 
-The online documentation of the bundle is in http://sonata-project.org/bundles/admin
+Demo
+----
 
 The demo website can be found in http://demo.sonata-project.org/admin/dashboard    
 **Username and password is:** ```admin```
 
+Documentation
+------------
+
+The online documentation of the bundle is in http://sonata-project.org/bundles/admin
+
 For contribution to the documentation you can find it on [Resources/doc](https://github.com/sonata-project/SonataAdminBundle/tree/master/Resources/doc).
 
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