Just create a new bookmark in your toolbar and paste the following code as URL (because we can't make bookmarlet links with GitHub markdown) :
javascript:!function(){s=document.createElement('script'),s.src='https://raw.github.com/gist/2932607/ddb79d0d67f5aea20083aa08dd6e056a927a5d66/bookmarklet.min.js?v='+~~(new Date),document.body.appendChild(s)}();