title: Modify django's username policy?
body: <p>Django default admin authentication module disallows use of the <code>\</code> char in usernames. How can I make it accept it?</p>
  
  <p>It looks like it's possible to edit <code>contrib/auth/models.py</code>'s username field's validator, but that won't do because it requires a change to django's base code.</p>