class AASM::Base

def attribute_name(column_name=nil)

This method is both a getter and a setter 
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