title: How to pull remote branch from somebody else's repo
body: <p>I've got a project hosted on GitHub which somebody has forked. On their fork, they've created a new branch "foo" and made some changes.  How do I pull their "foo" into a new branch also named "foo" in my repo?</p>
  
  <p>I understand they could submit a pull request to me, but I'd like to initiate this process myself.</p>
  
  <p>Assume the following:</p>
  
  <ol>
  <li>Because they forked my project, both our repos share the same 'history'</li>
  <li>Although GitHub shows their project was forked from mine, my local repository doesn't have any references to this person's project. Do I need to add theirs as a remote?</li>
  <li>I don't have a branch called "foo" yet - I don't know if I need to manually create this first.</li>
  <li>I definitely want this pulled into a separate branch and not my master.</li>
  </ol>