This short early adopter book details both how you'll upgrade existing web applications from Rails 4.2 to 5 and how to create new applications in Rails 5. The headline features, Rails API and Action Cable are each looked at in detail, building small example projects to demonstrate how to build a JSON API and add real-time interactions in order to create a single-page application. All the breaking changes are shown, along with how to fix your app to work with the new release. The improvements to ActiveRecord and the testing framework are fully detailed. After reading and using , you’ll be poised to move forward with building your apps with the latest major release of Ruby on Rails. What You'll Learn • Discover the new features in Rails 5 and how to upgrade your application from Rails 4.2 • Gain knowledge about the changes to ActiveRecord • See the improvements to the Rails testing framework • Build API servers using Rails API • Create WebSocket applications using Action Cable Who This Book Is For Existing Rails developers who are looking to quickly get up to speed with the changes in the new Rails 5 framework.