def field_i18n(field, *options)
  
  ['en', 'zh_tw'].each do |locale|
    field "#{field.to_s}_#{locale}".to_sym, *options
  end
  
  define_method(field) do
    self.send("#{field.to_s}_#{I18n.locale}")
  end
  
  define_method("#{field}=") do |value|
    ['en', 'zh_tw'].each do |locale|
      self.send("#{field.to_s}_#{locale}=", value)
    end
  end
end