title: git push is pushing to the wrong repo
body: <p>After recently taking a programming course online which required us to upload our homework assignments into Github, ever since then whenever I type <code>git push -u origin master</code> I get:</p>
  
  <pre><code>remote: Permission to my-github-username/mygithubrepo.git denied to rheros.
  fatal: unable to access 'https://github.com/my-github-username/mygithubrepo.git/': The requested URL returned error: 403
  </code></pre>
  
  <p><code>rheros</code> is the name of the repository that I used to push my homework assignments to.  Obviously, now I'm not using <code>rheros</code> anymore, yet the command line thinks I'm still trying to push to it.  I tried checking whether I have a faulty SSH key, but everything looks fine.  </p>
  
  <p>How can I make my command line effectively forget about the existence of a completely irrelevant directory that I pushed to before?  </p>
  
  <p><strong>EDIT</strong>
  <code>git remote --verbose</code> gives:</p>
  
  <pre><code>origin  https://github.com/my-github-username/mygithubrepo.git (fetch)
  origin  https://github.com/my-github-username/mygithubrepo.git (push)
  </code></pre>
  
  <p>So far, none of the suggestions below have helped me: it seems that the <code>rheros</code> repo is running somewhere in the background of my command line, and I can't figure out how to eliminate it.</p>