Rails bootstrap inline errors

boostrap_inline_errors.rb

module FormHelper

  def bootstrap_errors_for(attr, form, &block )
    errors = form.errors[attr]
    error_messages = errors.map{|error| content_tag(:span, error)}
    content = block_given? ? capture(&block) : "".html_safe
    noko_content = Nokogiri::HTML::DocumentFragment.parse(content)
    noko_content.css('.form-group')[0]['class'] = "#{noko_content.css('.form-group')[0]['class']} has-error" if errors.present?
    if error_messages.present?
      html_errors = content_tag(:div, :class => "errors" ) do
        error_messages.join("").html_safe
      end
      noko_content.css('.form-group').children.first.add_previous_sibling(html_errors)
    end

    noko_content.to_s.html_safe
  end
end