title: Upload untracked file with Heroku CLI
body: <p>Is it possible to upload an untracked file to Heroku using the CLI? Something like </p>
  
  <pre><code>$ heroku upload config/secrets.yml
  </code></pre>
  
  <p>I have a file that I do not want to track in my Github repository that is deploying to Heroku, but I need it to make the application work on Heroku.</p>