In this chapter, I go through the majority of the important changes to Rails, excluding Active Record and the testing framework.
While most of the changes seem small, there are some great refinements of the framework, making your day-to-day development work easier, allowing greater configuration and flexibility, and bringing the framework up to date.
I’ve omitted changes that are simply bug fixes or internal changes that don’t affect application development.
Ruby 2.2 or Higher
If you are upgrading from an earlier version of Rails, or just about to start a new Rails 5 project, the very first thing you need to know ...