title: Django 1.5 override abstractuser email field to be required and unique
body: <p>I have a custom user model extending AbstractUser. I have added two custom fields. But i want the default email field to be uniqe and required . I have searched a lot on the net, but could not find a good advice.</p>
  
  <p>Is it the right way to do that in extended usercreationform  with overridden 'clean_email' method?</p>
  
  <p>Thanx</p>