Rails6

Ruby Hash#transform_keys Accepts Key Mapping

Ruby Hash#transform_keys now also accepts a hash that maps the existing hash keys to new keys

Rails Adds Automatic Database Connection

Rails has added support for automatic database connection switching from primary to the replica

Rails 6.1 perform_enqueued_jobs at Option

Rails 6.1 has added at option to perform_enqueued_jobs test helper to run only jobs which are scheduled at or before the passed in time

Rails Disallowed Deprecations Support

Rails has added support to configure disallowed deprecations.

Rails has added a benchmark generator

Rails has added a benchmark generator for scripts to benchmark Rails application.

Rails 6 adds rails db:system:change command

Rails 6 adds rails db:system:change command to allow switching database configuration

Rails 6 ActiveSupport Unicode Deprecations

Rails 6 has deprecated methods in Unicode and Chars support for ActiveSupport in favor of using ruby 2.3+ String methods directly.

Rails 6.1 Adds Multiple Storage Services

Rails 6.1 adds support to configure storage services for individual attachment.

Webpacker is the new default in Rails 6

Webpacker is the new default JavaScript compiler instead of Sprockets in Rails 6

Rails 6 adds ActiveSupport::ParameterFilter

Rails 6 has moved ParameterFilter from ActionDispatch to ActiveSupport in order to support filtered attributes with ActiveRecord::Relation#inspect.