title: Maintain git repo inside another git repo
body: <p>Here's what I'd like:</p>
  
  <pre><code>REPO-A
    /.git
    /otherFiles
    /REPO-B
      /.git
      /moreFiles
  </code></pre>
  
  <p>I want to be able to push <em>all</em> of REPO-A's contents to REMOTE-A and <em>only</em> REPO-B to REMOTE-B.</p>
  
  <p>Possible?</p>