Overriding the method save() and delete() to insert a user with their information.

operator_models.py

# coding: utf8
from django.db import models

from django.contrib.auth.models import User, Permission

class Operator(models.Model):   
    user= models.ForeignKey(User,related_name='operator_user',blank=True,null=True,editable=False)
    name = models.CharField(max_length=80)
    username = models.CharField(max_length=30,unique=True)
    password = models.CharField(max_length=30)
    email = models.EmailField(max_length=255,unique=True)
    role = models.CharField(max_length=80,editable=False)
    phone = models.CharField(max_length=15)
    obs = models.TextField()

    class Meta():
        db_table = 'operators'
        ordering = ['nome']

        permissions = (
            ("view_operador","Can view operador"),
        )

    def __unicode__(self): return self.nome

    def save(self):
        if not self.id:
            user = User.objects.filter(username=self.username)
            if user:
                u = user[0]
            else:
                u = User.objects.create_user(self.username,self.email,self.password)

            u.save()

            # Register permissions
            u.user_permissions = [permission.id for permission in Permission.objects.filter(codename__icontains='operator')]
            self.user= u
        else:
            self.user.username = self.username
            self.user.email = self.email
            self.user.set_password(self.password)
            self.user.save()
        super(Operador, self).save()

    def delete(self, id_operator):

        operador = Operator.objects.get(pk=id_operator)
        user = User.objects.get(id=operador.user.id)
        user.delete()

        super(Operator, self).delete()