I followed the Angular 2 tutorial, with DART, and then replaced the mock service with a Rails 5 API only backend. I then modified the hero_service to utilise the new backend. Feel free to hit me up with any questions.
To launch the Angular APP, you'll need the Dart SDK. Once installed
$ pub get
$ pub serve
To run the Rails backend, simply type
$ bundle install
$ rails s
Open a browser at http://localhost:8080 and you're ready to go.
Licence is MIT