Updating Heroku Readme

Author: zardra

heroku/README.md

@@ -12,8 +12,7 @@ This is a sample client for Facebook's [Webhooks](https://developers.facebook.co
     [![Deploy](https://www.herokucdn.com/deploy/button.svg)](https://heroku.com/deploy?template=https://github.com/fbsamples/graph-api-webhooks-samples)
 
 ### Instagram Subscription API
-
-1. Refer to Facebook's [Webhooks sample app documentation](https://developers.facebook.com/docs/webhooks/sample-apps) to see how to use this app.
+1. Register an [Instagram API client](https://instagram.com/developer/clients/manage/).
 1. Deploy the sample app on Heroku with this button:
 
     [![Deploy](https://www.herokucdn.com/deploy/button.svg)](https://heroku.com/deploy?template=https://github.com/fbsamples/graph-api-webhooks-samples)