title: Django Admin - Allow models to be shown for is_staff users
body: <p>I need to make some Django models available for <code>is_staff=True</code> users in the Django admin interface.
  I do not want to go for each user and assign them permissions or group permissions to the staff users.</p>
  
  <p>Which method do I need to override in <code>ModelAdmin</code> or <code>BaseModelAdmin</code> class or is there any other simpler way?
  I am using Django 1.4 Version</p>