title: how to address Git error "the requested upstream branch 'upstream/master' does not exist"
body: <p>I am attempting to follow some steps to contribute to a repository on GitHub and one of the steps is not working. The steps are here: <a href="https://github.com/wdbm/qTox/blob/master/CONTRIBUTING.md#how-to-open-a-pull-request" rel="noreferrer">https://github.com/wdbm/qTox/blob/master/CONTRIBUTING.md#how-to-open-a-pull-request</a>.</p>
  
  <p>I fork the repository on GitHub.</p>
  
  <p>I clone the repository:</p>
  
  <pre><code>git clone https://github.com/&lt;YOUR_USER&gt;/qTox.git
  </code></pre>
  
  <p>I access the directory of the local repository:</p>
  
  <pre><code>cd qTox
  </code></pre>
  
  <p>I add the upstream remote in order to be able to fetch from the upstream repository:</p>
  
  <pre><code>git remote add upstream https://github.com/qTox/qTox.git
  </code></pre>
  
  <p>I attempt to point the local master branch to the upstream repository:</p>
  
  <pre><code>git branch master --set-upstream-to=upstream/master
  </code></pre>
  
  <p>This command fails with the following error message:</p>
  
  <pre><code>error: the requested upstream branch 'upstream/master' does not exist
  hint: 
  hint: If you are planning on basing your work on an upstream
  hint: branch that already exists at the remote, you may need to
  hint: run "git fetch" to retrieve it.
  hint: 
  hint: If you are planning to push out a new local branch that
  hint: will track its remote counterpart, you may want to use
  hint: "git push -u" to set the upstream config as you push.
  </code></pre>
  
  <p>How should I address this error? I am using Git 2.9.3.</p>