title: Move all files of a git directory into subdirectory and maintain history
body: <p>How can I move all the files of my current directory into a new directory and retain the history.</p>
  
  <p>I have tried:</p>
  
  <pre><code>git mv . old_app
  </code></pre>
  
  <p>But I get:</p>
  
  <pre><code>fatal: bad source, source=, destination=old_app/
  </code></pre>