This demo shows a Rails 5 API with Swagger documentation and Test::Unit and Rspec testing. It uses ActiveModel::Serializers to comply with the JSON+API hypermedia spec.
Install Rails 5:
git clone https://github.com/rails/rails.git
cd rails/
bundle install
Generate API:
bundle exec railties/exe/rails new ../books --edge --dev --api
Create Scaffold:
bundle exec rails generate scaffold books title description:text page_count:integer
Migrate the database:
bundle exec rake db:migrate