Sample application, exists to demo the presentation layer of V4 and the documentation that that presentation layer would output.
Start the rails server on port 3005 and navigate to localhost:3005/redoc_index.html.
Swagger-ui is unfortunately more of a pain to get started. You have to clone the swagger-ui project from github and then open the file ~/swagger-ui/dist/index.html in your web browser. With the rails server running, change the URL in the top text input to be "http://localhost:3005/api/swagger_doc.json." You should see the docs for this project appear.
Presenters are inside app/presenters, and all subclass app/presenter/presenter.rb.