class Client(models.Model):
    user = models.ForeignKey(settings.AUTH_USER_MODEL, related_name='client', on_delete=models.CASCADE)
    date_of_birthday = models.DateField(_('date of birthday'), null=True, blank=True,)
    gender = models.CharField(choices=GENDERS, max_length=6, null=True, blank=True,)

    def __str__(self):
        return "{}".format(self.user)