Add readme

Author: jbarat

README.md

@@ -1 +1,8 @@
-<img src='https://circleci.com/gh/jbarat/LoadingButton.png'>
+<img src='https://circleci.com/gh/jbarat/LoadingButton.png'>
+
+Simple app to experiment with a more complex custom button.
+The idea is that this button would start a webservice call and
+depending on the result of the webservice call it would change into
+success or fail state.
+
+<img src="/demo.gif" width="49%">