Add gittip button

Author: imakewebthings

README.md

@@ -61,4 +61,9 @@ If you would like to contribute a patch to deck.js please do as much as you can
 
 Copyright (c) 2011-2013 Caleb Troughton
 
-Dual licensed under the [MIT license](https://github.com/imakewebthings/deck.js/blob/master/MIT-license.txt)
+Dual licensed under the [MIT license](https://github.com/imakewebthings/deck.js/blob/master/MIT-license.txt)
+
+## Donations
+
+[![Gittip donate
+button](http://img.shields.io/gittip/imakewebthings.png)](https://www.gittip.com/imakewebthings/ "Donate weekly to this project using Gittip")