title: Include a GitHub submodule automatically in download
body: <p>I have a GitHub repository and use another project as a submodule. This submodule is also in <code>.gitmodules</code>, the code below:</p>
  <pre><code>[submodule &quot;inc/tha&quot;]
      path = inc/tha
      url = git://github.com/zamoose/themehookalliance.git
  </code></pre>
  <p>See also in view on GitHub.</p>
  <p><img src="https://i.stack.imgur.com/u1RX2.png" alt="submodule in repo" /></p>
  <p>How is it possible to download my GitHub repository, including the submodule files?</p>