class Users(models.Model):
group_id = models.IntegerField()
name = models.CharField(max_length=100, null=True)
email = models.CharField(max_length=100, null=True, unique=True)
password = models.CharField(max_length=255, null=False)
remember_token = models.CharField(max_length=255, null=True)
activated = models.IntegerField(default=1)
banned = models.IntegerField(default=0)
ban_reason = models.CharField(max_length=255, null=True)
otp = models.CharField(max_length=255, null=True)
created_at = models.DateTimeField()
updated_at = models.DateTimeField(null=True)

USERNAME_FIELD = 'email'
REQUIRED_FIELDS = ['username','password',]

class Meta:
    managed = False
    db_table = 'users'

File "/usr/local/lib/python2.7/dist-packages/django/core/handlers/base.py", line 149, in get_response
response = self.process_exception_by_middleware(e, request)
File "/usr/local/lib/python2.7/dist-packages/django/core/handlers/base.py", line 147, in get_response
response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "/usr/local/lib/python2.7/dist-packages/django/views/decorators/csrf.py", line 58, in wrapped_view
return view_func(*args, **kwargs)
File "/usr/local/lib/python2.7/dist-packages/django/views/generic/base.py", line 68, in view
return self.dispatch(request, *args, **kwargs)
File "/usr/local/lib/python2.7/dist-packages/rest_framework/views.py", line 466, in dispatch
response = self.handle_exception(exc)
File "/usr/local/lib/python2.7/dist-packages/rest_framework/views.py", line 463, in dispatch
response = handler(request, *args, **kwargs)
File "/usr/local/lib/python2.7/dist-packages/rest_framework_jwt/views.py", line 56, in post
if serializer.is_valid():
File "/usr/local/lib/python2.7/dist-packages/rest_framework/serializers.py", line 213, in is_valid
self._validated_data = self.run_validation(self.initial_data)
File "/usr/local/lib/python2.7/dist-packages/rest_framework/serializers.py", line 410, in run_validation
value = self.validate(value)
File "/usr/local/lib/python2.7/dist-packages/rest_framework_jwt/serializers.py", line 50, in validate
user = authenticate(**credentials)
File "/usr/local/lib/python2.7/dist-packages/django/contrib/auth/__init__.py", line 74, in authenticate
user = backend.authenticate(**credentials)
File "/usr/local/lib/python2.7/dist-packages/django/contrib/auth/backends.py", line 17, in authenticate
user = UserModel._default_manager.get_by_natural_key(username)
AttributeError: 'Manager' object has no attribute 'get_by_natural_key'

INSTALLED_APPS = [
'django.contrib.admin',
'django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.sessions',
'django.contrib.messages',
'django.contrib.staticfiles',
'testing',
'rest_framework',
'rest_framework_jwt',
]

REST_FRAMEWORK = {
'DEFAULT_PERMISSION_CLASSES': (
    'rest_framework.permissions.IsAuthenticated',
),
'DEFAULT_AUTHENTICATION_CLASSES': (
    'rest_framework.authentication.SessionAuthentication',
    'rest_framework.authentication.BasicAuthentication',
    'rest_framework_jwt.authentication.JSONWebTokenAuthentication',
),
}
AUTH_USER_MODEL = 'testing.Users'