field with errors

environment.rb

ActionView::Base.field_error_proc = Proc.new do |html_tag, instance|
  if instance.instance_of? ActionView::Helpers::Tags::Label
    html_tag
  else
    %(<div class="form-field error">#{html_tag}<small class="error">&nbsp;#{[*instance.error_message].join(', ')}</small></div>).html_safe
  end
end