update readme to instruct people to issue pull requests to dev

Author: bradrobertson

README.md

@@ -1,4 +1,9 @@
 [jQuery Tools](http://flowplayer.org/tools/) - The Missing UI library for the Web
 ================================
 
-jQuery Tools is a collection of the most important user-interface components for modern websites. Used by large sites all over the world.
+jQuery Tools is a collection of the most important user-interface components for modern websites. Used by large sites all over the world.
+
+##Contributing
+
+Please issue pull requests to the [dev branch](https://github.com/jquerytools/jquerytools/tree/dev).  
+This is where active development takes place, we then merge changes into master for releases