Added heroku deploy button

Author: x1wins

README.md

@@ -5,6 +5,8 @@
 [![contributions welcome](https://img.shields.io/badge/contributions-welcome-brightgreen.svg?style=flat)](https://github.com/dwyl/esta/issues)
 [![Known Vulnerabilities](https://snyk.io/test/github/x1wins/tutorial-rails-rest-api/badge.svg)](https://snyk.io/test/github/x1wins/tutorial-rails-rest-api)
 
+[![Deploy](https://www.herokucdn.com/deploy/button.svg)](https://heroku.com/deploy)
+
 
 
 # Tutorial rails rest api
@@ -1109,4 +1111,4 @@ https://gist.github.com/kelvinn/6a1c51b8976acf25bd78
         -H "Authorization: eyJhbGciOiJIUzI1NiJ9.eyJ1c2VyX2lkIjoxLCJleHAiOjE1OTA0MzExOTN9.GtlH3xbINMNSKAU00np5njGtDWEcXXOHZ2zbjKsgr24" \
         http://localhost:3000/api/v1/posts?category_id=1&page=1    
     ```
-  
+