refactor models.py into a module

gistfile1.py

# registration/models <- en vez de models.py
# dentro models/__init__.py
#              /user.py
#              /foo.py

# user.py
class User(models.Model):
    pass

# foo.py
class Foo(models.Model):
    pass

# __init__.py
from .user import User
from .foo import Foo