Integrate AMS 0.9 with new Rails 5 project

[oyeanuj]

Source issue: rails-api/active_model_serializers#1923
Latest update: rails-api/active_model_serializers#1923 (comment)

Success Criteria:

1. Get Rails 5 and AMS 9 working together, so that one can use the generators to create a new resource, serializers and have it all working for a basic example.
2. Make necessary PR to the AMS repo to get this to work.

Feel free to create a new Rails 5 Project with ActiveModelSerializer 0.9 if needed.

[oyeanuj]

Fixed by rails-api/active_model_serializers#2167

[hiradyazdan]

@oyeanuj has this been merged, it looks like this has been left untouched for a long time?