Add Yeah Web to README

Author: Artur Ostręga

README.md

@@ -5,3 +5,5 @@ Ruby video game framework, in revision
 [Demos](https://github.com/yeahrb/yeah/wiki/Demos)
 
 [Latest alpha release (version 0.4.2)](https://github.com/yeahrb/yeah/tree/0.4.2)
+
+[Yeah Web](https://github.com/yeahrb/yeah-web)