Improve natural key support in the UserOptions model.

Signed-off-by: Roberto Rosario <roberto.rosario.gonzalez@gmail.com>

mayan/apps/user_management/models.py

@@ -4,6 +4,8 @@ from django.conf import settings
 from django.db import models
 from django.utils.translation import ugettext_lazy as _
 
+from .managers import UserOptionsManager
+
 
 class UserOptions(models.Model):
     user = models.OneToOneField(
@@ -15,6 +17,8 @@ class UserOptions(models.Model):
         verbose_name=_('Forbid this user from changing their password.')
     )
 
+    objects = UserOptionsManager()
+
     class Meta:
         verbose_name = _('User settings')
         verbose_name_plural = _('Users settings')