Custom input for simple_form using twitter bootstrap

prepend_checkbox_input.rb

class PrependCheckboxInput < SimpleForm::Inputs::Base
  def input
    "<div class='input-prepend'>
      <label class='add-on active' title='#{options[:tooltip]}' rel='tooltip' >
        #{@builder.check_box(attribute_name.to_s + '_check')}
      </label>
      #{@builder.text_field(attribute_name,  input_html_options)}
      <span class='help-inline'>
        #{options[:help]}
      </span>
    </div>".html_safe
  end
end

view.html.erb

  <%= f.input :name, :as => :prepend_checkbox, :tooltip => "Has name?", :help => "Please insert your name" %>