Rails adds ActiveRecord API for switching multiple database connectionsRails adds ActiveRecord API connects_to and connected_to for switching connections to support multiple databases.
Rails introduces disallowed deprecations in ActiveSupportRails has added support to configure disallowed deprecations.
Rails has added a benchmark generatorRails has added a benchmark generator for scripts to benchmark Rails application.
Rails adds support for if_exists/if_not_exists on remove_column/add_column in migrationsRails adds support for if_exists/if_not_exists on remove_column/add_column in migrations to silently ignore migrations
Rails 6 adds rails db:system:change commandRails 6 adds rails db:system:change command to allow switching database configuration
Rails 6 - ActiveSupport Deprecations in Unicode and Chars support in favour of StringRails 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 support for multiple storage services to Active StorageRails 6.1 adds support to configure storage services for individual attachment.
Rails adds ActiveRecord::Relation#annotate for adding SQL comments to ActiveRecord::Relation queriesRails adds ActiveRecord::Relation#annotate for adding SQL comments to ActiveRecord::Relation queries
Ruby 2.7 - Singleton class yield syntax throws a warningRuby 2.7 singleton class yield syntax is warned and will be deprecated in Ruby 3.0.
How to pass arguments to methods in ruby and how it affects their arityDeep dive into different ways of passing arguments to methods and how it affects their arity