* Fix user creation with group_ids via API
Creating a user via POST /api/user/ with the 'group_ids' field raised
TypeError: User() got unexpected keyword arguments: 'group_ids'.
The write-only 'group_ids' field was only handled on update.
- Declare 'group_ids' in SKIP_CREATE_FIELDS so it is not passed to the model
- Assign the groups after the user instance is created
- Add API test covering user creation with and without groups
* Bump API version
Fran Quinto
