Profile model

# FILE models.py
from django.contrib.auth.models import User
from django.db import models

class Profile(models.Model):
    user = models.OneToOneField(User)
    nome = models.CharField(u'nome', null=True, blank=True, max_length=80)
    matricula = models.CharField(u'matricula', null=True, blank=True, max_length=80)
    cargo = models.CharField(u'cargo', null=True, blank=True, max_length=80)


# FILE migrations/xxxx_foo.py
# -*- coding: utf-8 -*-
from __future__ import unicode_literals

from django.contrib.auth.models import User
# from django.contrib.auth import get_user_model
from django.db import migrations


def create_profiles(apps, schema_editor):
    Profile = apps.get_model('core', 'Profile')

    print User     # <class 'django.contrib.auth.models.User'>
    print Profile  # <class 'Profile'>

    for user in User.objects.all():
        profile = Profile(user=user)
        profile.save()


class Migration(migrations.Migration):
    dependencies = [
        ('foo', 'xxxy_foo'),
    ]

    operations = [
        migrations.RunPython(create_profiles),
    ]


# ERROR:
#   File ".../migrations/0008_auto_20150712_1502.py", line 19, in create_profiles
#     profile = Profile(user=user)
#   File ".../lib/python2.7/site-packages/django/db/models/base.py", line 468, in __init__
#     setattr(self, field.name, rel_obj)
#   File ".../lib/python2.7/site-packages/django/db/models/fields/related.py", line 627, in __set__
#     self.field.rel.to._meta.object_name,
# ValueError: Cannot assign "<User: admin>": "Profile.user" must be a "User" instance.