define_change_tracking_methods

# File activerecord/lib/active_record/associations/builder/belongs_to.rb, line 153
    def self.define_change_tracking_methods(model, reflection)
      model.generated_association_methods.class_eval         def #{reflection.name}_changed?          association = association(:#{reflection.name})          deprecated_associations_api_guard(association, __method__)          association.target_changed?        end        def #{reflection.name}_previously_changed?          association = association(:#{reflection.name})          deprecated_associations_api_guard(association, __method__)          association.target_previously_changed?        end, __FILE__, __LINE__ + 1
    end