title: How to remove permission from a role only for a particular user in spatie/laravel-permission?
body: <p>Let's say that I have three users in my system <code>Sam</code>, <code>John</code> and <code>Sarah</code>.
  All three have a role of <code>editor</code> which gives them permission to <code>create article</code>, <code>edit article</code>, <code>publish article</code> and <code>delete article</code>.
  Now for some reason, I don't want <code>Sam</code> to have permission to <code>delete article</code> but still have the role of <code>editor</code>.</p>
  
  <p>How can I achieve this in Laravel with this spatie/laravel-permission package?
  (Assume that I may have to do such operation on a somewhat regular basis and there are after some time I may assign back <code>delete article</code> again the <code>Sam</code>. And there are way too many permissions in any role, so i can't do it manually.)</p>