workaround for state_machine in Rails 4

pluginaweek/state_machine#295

config/initializers/state_machine.rb

@@ -0,0 +1,14 @@
+# Rails 4.1.x and StateMachine don't play nice
+# https://github.com/pluginaweek/state_machine/issues/295
+
+require 'state_machine/version'
+
+unless StateMachine::VERSION == '1.2.0'
+  # If you see this message, please test removing this file
+  # If it's still required, please bump up the version above
+  Rails.logger.warn "Please remove me, StateMachine version has changed"
+end
+
+module StateMachine::Integrations::ActiveModel
+  public :around_validation
+end