HACK StateMachine gem to make it work with ActiveRecord 4.2

state_machine.rb

# HACK to enable using protected methods from Rails 4.2 and initial states as default attributes for ActiveRecord
module StateMachine
  module Integrations
    module ActiveModel
      public :around_validation
    end

    module ActiveRecord
      public :around_save

      def define_state_initializer
        define_helper :instance, <<-end_eval, __FILE__, __LINE__ + 1
          def initialize(*)
            super do |*args|
              self.class.state_machines.initialize_states(self)
              yield(*args) if block_given?
            end
          end
        end_eval
      end
    end
  end
end