the user registration functionality has been removed as part of these commits:

https://github.com/cvasilak/aerogear-push-quickstarts/commit/efe4602de7e845efcc1ee0cedd0cc4f6fd7ed3e6

https://github.com/cvasilak/aerogear-push-quickstarts/commit/3d0e5f70b0315ab3dbafe30b8ba61495165a27d9