Merge pull request #2858 from metabase/fix-heroku-branch-deploy-stable-build-link

fix stable build link in readme [ci skip]

README.md

@@ -99,7 +99,7 @@ Metabase also allows you to hit our Query API directly from Javascript to integr
 
 # Danger zone
 
-The button below will deploy the branch where this README.md lives into Heroku. The developers use it to quickly spin up a copy of Metabase. We DO NOT recommend you using this for production, but rather using a [stable build ](www.metabase.com/start)
+The button below will deploy the branch where this README.md lives into Heroku. The developers use it to quickly spin up a copy of Metabase. We DO NOT recommend you using this for production, but rather using a [stable build](http://metabase.com/start)
 
 [![Deploy](https://www.herokucdn.com/deploy/button.svg)](https://heroku.com/deploy)