Create Request.creator relationship

- Rename creator_id to user_id

tests/models/test_requests.py

@@ -1,4 +1,4 @@
-from tests.factories import RequestFactory
+from tests.factories import RequestFactory, UserFactory
 from atst.domain.requests import Requests, RequestStatus
 
 
@@ -19,3 +19,10 @@ def test_pending_ccpo_approval_requires_ccpo():
     request = Requests.set_status(request, RequestStatus.PENDING_CCPO_APPROVAL)
 
     assert Requests.action_required_by(request) == "ccpo"
+
+
+def test_request_has_creator():
+    user = UserFactory.create()
+    request = RequestFactory.create(creator=user)
+
+    assert request.creator == user