mixed Auth::addUser ( 
     string $username
      , string $password
      , mixed $additional = ''
    )
Add a new user to the Auth Container.
$username
       the username of the new user
$password
       the password of the new user
$additional = ''
       additional options to be passed to the creation of the new user. Each Auth_Container has different options for these, please see the containers documentation for what is supported.
     mixed - 
     TRUE on success, a PEAR Error on failure.
    
This function can not be called statically.
Not all Auth Containers implement this functionality.