Meteor: Login with Github on Heroku

It is a bit tricky to setup Meteor application to login with external service on Heroku (if you want to use your own domain). You need to do the following:

1. While creating an application on Github, you have to use the same pattern for URLs. If you choose to use www prefix, use it everywhere.
   
2. Then go to the console and set ROOT_URL (heroku config:add ROOT_URL=http://www.templhub.com). You need to have it EXACTLY the same as in GitHub application configuration.