title: A PHP Github class to do updates only
body: <p>I have a PHP application which i want to extend with self updating capabilities. To me the best solution for this is to use some sort of SVN protocol to update my PHP application.</p>
  
  <p>Currently my application is hosted on Github, so i'm really looking for a class which is able to do update my local application with the latest version on Github.</p>
  
  <p>Is there such a class available? I'd like to have a class which does just that. I don't need functionality to commit code, list files in a repository or things like that. All it needs to do is an update.</p>
  
  <p>So i'm looking for a <strong><em>pure</em></strong> PHP class which can do this, which doesn't need any Github application to be installed on the machine in order to work.</p>
  
  <p>So something simple like:</p>
  
  <pre><code>$repo = new Github ( 'path/to/local/repo', 'url/to/remote/repo', 'master' );
  $repo-&gt;update ( );
  </code></pre>