title: Git - Push a directory and then ignore it
body: <p>I have a folder containing all my http requests files that I execute on PhpStorm. 
  I added first this folder to my gitignore file :</p>
  
  <pre><code>/app/http/
  </code></pre>
  
  <p>Then I forced to push it to my remote repository:</p>
  
  <pre><code>git add -f app/http
  git commit -m 'http folder added'
  git push
  </code></pre>
  
  <p>But after that, my folder is not ignored.
  How can I ignore it after pushed it ?</p>