title: Unable to Push After bfg Cleaner
body: <p>Followed these steps to remove some content from my <a href="https://rtyley.github.io/bfg-repo-cleaner/" rel="nofollow noreferrer">repository</a>. </p>
  
  <p>However, when I did a <code>git push</code>, I got the below message:</p>
  
  <blockquote>
    <p>Writing objects: 100% (28/28), 6.72 KiB | 1.34 MiB/s, done.
        Total 28 (delta 18), reused 18 (delta 9)
        remote: error: denying non-fast-forward refs/heads/master (you should pull first)
        remote: error: denying non-fast-forward refs/heads/multiplicity_refinement (you should pull first)
        To ssh://path_to_repo/repo_name.git
         ! [remote rejected] master -> master (non-fast-forward)
         ! [remote rejected] multiplicity_refinement -> multiplicity_refinement (non-fast-forward)
        error: failed to push some refs to 'ssh://path_to_repo/repo_name.git'</p>
  </blockquote>