def method_missing(method_name, *args, &block)
    if method_name =~ /^swap_(.+)_with(!?)$/
      property = $1
      is_bang  = $2 == '!'
      sibling  = args[0]

      old_sibling_property = sibling.send(property)
      old_self_property    = self.send(property)
      puts property
      sibling.send("#{propery}=", old_self_property)
      self.send("#{property}=", old_sibling_property)

      [self, sibling].collect(&:save) if is_bang
      return self
    end
  end