title: git: How do you add an external directory to the repository?
body: <p>I want to add an external directory to an existing repository.</p>
  
  <p>External Dir:
  /home/some/directory</p>
  
  <p>Working Dir:
  /htdocs/.git</p>
  
  <p>If I attempt the following command from the /htdocs dir:</p>
  
  <blockquote>
    <p>git add /home/some/directory</p>
  </blockquote>
  
  <p>I get an error:
  fatal: '/home/some/directory' is outside repository </p>