[API Tests] Users module - Create User

Hi devs,

I’m getting a 500 when trying to create a new User.

Test Case: https://github.com/dhis2/api-tests/blob/master/modules/users/user.js#L13

Failing Job: https://travis-ci.org/dhis2/api-tests/jobs/169493320#L2057

Payload: https://github.com/dhis2/api-tests/blob/master/data/users.js#L4

“message”: “attempted to assign id from null one-to-one property [org.hisp.dhis.user.UserCredentials.userInfo]”

BR,

Paulo