• [Maintenance] Declare rake in the Gemfile. It came only through karafka-rdkafka, which will stop depending on it for precompiled platform gems.
• [Enhancement] Make Taggable::Tags#add with the value a tag already has and #delete of a missing tag about 6x faster on MRI and JRuby.
• [Fix] Make Contractable::Result#errors keep the first error when one path has more than one, instead of the last.
• [Fix] Make Contractable::Contract#call return a successful result for a contract with no rules of its own, instead of raising NoMethodError.
• [Fix] Make Contractable::Contract.rules return an empty Array for a contract with no rules, instead of nil.