This short early adopter book details both how you'll upgrade existing web and other applications from Rails 4.2 to 5 and how to create new applications in Rails 5. The headline features, Rails API and ActionCable, are each looked at in detail, building small example projects to demonstrate how to build a JSON API, add real-time notifications to a page and how to create a single-page application.
All the breaking changes are shown, along with how to fix your app to work with the new API, and the improvements to ActiveRecord and the testing
framework are fully detailed. After reading and using Rails 5 Revealed, you'll be poised to move forward with building your apps with the new Rails 5 as it stands now and when it finalizes.