Rails Error field template bootstrap 3

application.rb

ActionView::Base.field_error_proc = Proc.new do |html_tag, instance|
  html = %(<div class="error">#{html_tag})
  html += %(<small>#{instance.error_message.to_a.to_sentence}</small>).html_safe unless html_tag =~ /^<label/
  html += %(</div>)
  html.html_safe
end

application2.rb

# ...

ActionView::Base.field_error_proc = Proc.new do |html_tag, instance|
  html = %(<div class="error">#{html_tag})
  html += %(&nbsp;<small style='color: red;'>#{instance.error_message.to_a.to_sentence}</small>).html_safe unless html_tag =~ /^<label/
  html += %(</div>)
  html.html_safe
end