title: 'heroku' does not appear to be a git repository
body: <p>When I try to push my app to Heroku I get this response:</p>
  
  <pre><code>fatal: 'heroku' does not appear to be a git repository
  fatal: Could not read from remote repository.
  
  Please make sure you have the correct access rights
  and the repository exists.
  </code></pre>
  
  <p>I have tried 'heroku keys:add' but still comes up with the same result.
  I already have an ssh key for my GitHub account.</p>