title: Simple regex in Gruntfile
body: <p>I have the following line in my <code>Gruntfile</code>. </p>
  
  <p><code>js
  files: ['&lt;%= yeoman.app %&gt;/scripts/{,*/}*.coffee'],
  </code></p>
  
  <p>Could someone be so kind as tell me what <code>{,*/}*</code> mean? I know it's trying to match all <code>.coffee</code> files in the scripts folder, but I want to know how it does that.</p>