title: Creating an official github mirror
body: <p>How do I create a github mirror for an external git repository, such that it appears as "real mirror", e.g., as in <a href="https://github.com/mirrors" rel="noreferrer">https://github.com/mirrors</a>?</p>
  
  <p>So far, I set up a mirror using:</p>
  
  <pre><code>cd /path/to/bare/repository
  git remote add --mirror github git@github.com:user/repo.git
  </code></pre>
  
  <p>and configure the post receive hook to do a <code>git push --quiet github</code>. This way, however, github does not recognize the mirror.</p>
  
  <p>Any ideas how to do it the github way, such that "Mirrorred from" appears underneath the repostiory name?</p>