Remove rails new --javascript

The --javascript option for new Rails apps could install any gem ending in -rails. From now you'll have to add jquery-rails to your Gemfile manually.

Properly sourced fourty_two

The new documentation now has the answer to life the universe and everything.

Per subclass system testing driver overrides

Your system testing test case subclasses all have a designated driver. Now you can designate another driver in case the test case calls for it.

reverse_merge aliased to with_defaults

One for the aesthetics department: with_defaults has emerged as an alias for reverse_merge. So now options.with_defaults(creator: @current_user) makes your intent clearer.

Fixed rails-ujs.js module support

Once Rails 5.1 ships proper you'll be able to require rails-ujs from your JS again.