Copy this gist and customise it to your liking.
- Run Brakeman and resolve any issues where required
 - Run rails best practices and resolve any warnings
 - Run full test suite and make sure all tests are passing
 - Make sure no dummy email addresses are left in any notification emails (eg contact form)
 - Make sure production assets compile correct (eg files in vendor, etc, compile and are not 404'ing in production environment)
 - Make sure environment variables are setup correctly (need new Heroku, AWS)