Ruby on Rails 4.1 Release Notes — Ruby on Rails Guides
7章は、Active Modelです。
7 Active Model
7.1 Deprecations
・Deprecate Validator#setup
7.2 Notable changes
・Added new API methods reset_changes and changes_applied to ActiveModel::Dirty that control changes state.
See Also
Ruby on Rails 4.1 Release Notes
・#1(Rails4.1へのupgrade方法)
・#2(Rails4.1の主な機能)
・#3(Railties)
・#4(Action Pack)
・#5(Action Mailer)
・#6(Active Record)
・#7(Active Model)
・#8(Active Support)