Merge pull request #209 from facetostool/feature

change method to check attribute_name

lib/aasm/persistence/active_record_persistence.rb

@@ -166,7 +166,7 @@ module AASM
         def aasm_ensure_initial_state
           # checking via respond_to? does not work in Rails <= 3
           # if respond_to?(self.class.aasm.attribute_name) && send(self.class.aasm.attribute_name).blank? # Rails 4
-          if attributes.key?(self.class.aasm.attribute_name.to_s) && send(self.class.aasm.attribute_name).blank?
+          if attribute_names.include?(self.class.aasm.attribute_name.to_s) && send(self.class.aasm.attribute_name).blank?
             aasm.enter_initial_state
           end
         end