title: Group checkboxes needs required with bootstrap in rails3
body: <p>I am using bootstrap for templating. I have a group of checkboxes. I want to use <code>required</code> property of <code>bootstrap</code> but, when I want to use it for group of checkboxes not for individual. </p>
  
  <p>Is there is any way to impletement this.
  Here is the reference image <a href="http://grab.by/Hm5m" rel="nofollow">http://grab.by/Hm5m</a></p>