Add Deploy to Heroku button

Author: sarbull

Diff for: README.md

@@ -2,6 +2,8 @@
 
 [![Build Status](https://api.travis-ci.org/sarbull/blog-api.svg?branch=master)](https://travis-ci.org/sarbull/blog-api)
 
+[![Deploy to Heroku](https://www.herokucdn.com/deploy/button.svg)](https://heroku.com/deploy?template=https://github.com/sarbull/blog-api/tree/master)
+
 Blog's API using Spring and JPA.
 
 # Tools