title: Git branch no tracking information
body: <p>After git pull I get this output. </p>
  
  <pre><code>There is no tracking information for the current branch.
  Please specify which branch you want to merge with.
  See git-pull(1) for details
  
  git pull &lt;remote&gt; &lt;branch&gt;
  
  If you wish to set tracking information for this branch you can do so with:
  
  git branch --set-upstream-to=origin/&lt;branch&gt; my_branch
  </code></pre>
  
  <p>Problem is that I have created that branch and have done tones of commits on this branch and switching to other branches and getting back to this one. Than a new user added few commits and after that I am getting this message.</p>
  
  <p>My question is <strong>not how to fix this I want to know what cause this</strong> and how to prevent it from happening again. </p>