Update README to explain use in WriteFreely

Author: thebaer

README.md

@@ -5,4 +5,4 @@ Write.as web core
 [![#writefreely on freenode](https://img.shields.io/badge/freenode-%23writefreely-blue.svg)](http://webchat.freenode.net/?channels=writefreely)
 [![Discuss on our forum](https://img.shields.io/discourse/https/discuss.write.as/users.svg?label=forum)](https://discuss.write.as/c/development)
 
-web-core holds components of the [Write.as](https://write.as) web application.
+web-core holds components of the [WriteFreely](https://writefreely.org) web application, and is shared with other [Write.as](https://write.as) products, like [Snap.as](https://snap.as).