fix about.md

Author: aquynh

about.md

@@ -8,7 +8,7 @@ Having questions on how to use Keystone?
 
 Reporting bugs, or wanting to discuss about technical aspects of the framework?
 
-Want to let us know you are happily using Unicorn for your products/training/works?
+Want to let us know you are happily using Keystone for your products/training/works?
 
 - [Mailing list](http://www.freelists.org/list/keystone-engine) would be the best method to contact us. This is the place for long conversations.