def attribute_name(column_name=nil)
      if column_name
        @state_machine.config.column = column_name.to_sym
      else
        @state_machine.config.column ||= :aasm_state
      end
      @state_machine.config.column
    end
def attribute_name(column_name=nil)
      if column_name
        @state_machine.config.column = column_name.to_sym
      else
        @state_machine.config.column ||= :aasm_state
      end
      @state_machine.config.column
    end
This method is both a getter and a setter