Auth::addUser() -- add a new user
Description
     Add a new user to the Auth Container.
    
Parameter
     
- string
        $username
         
         the username of the new user
        
- string
        $password
         
         the password of the new user
        
- mixed
        $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.
        
 
    Return value
     mixed - 
     TRUE on success, a PEAR Error on failure.
    
Note
This function can not be called
statically.
     Not all Auth Containers implement this functionality.