title: Add symlinks to git repository
body: <p>I'm working on a little library and it depends on another github project.</p>
  
  <p>I know that
  <a href="http://github.com/ajaxorg/cloud9/tree/1b1401f/support" rel="nofollow noreferrer">some projects</a>
  add symlinks. How exactly do you do that?</p>