Add README.md
Add README.md

Example usage grabbed from blog post.

Change-Id: Ia2623eb55ba1609e0823e7947394d3ec12f4f9aa
Reviewed-on: https://gerrit.causes.com/22954
Tested-by: Joe Lencioni <1dd72cf724deaab5db236f616560fc7067b734e1@causes.com>
Reviewed-by: Aiden Scandella <1faf1e8390cdac9204f160c35828cc423b7acd7b@causes.com>

causes/method-proxy-js