diff --git a/encoach_api/controllers/classrooms.py b/encoach_api/controllers/classrooms.py
index 7d63c6b..585304d 100644
--- a/encoach_api/controllers/classrooms.py
+++ b/encoach_api/controllers/classrooms.py
@@ -25,7 +25,7 @@ class ClassroomsController(EncoachMixin, http.Controller):
 
             admin = kwargs.get('admin')
             if admin:
-                domain.append(('admin_ids', 'in', [int(admin)]))
+                domain.append(('admin_id', '=', int(admin)))
 
             entity_id = kwargs.get('entityID')
             if entity_id:
@@ -51,7 +51,7 @@ class ClassroomsController(EncoachMixin, http.Controller):
 
             vals = {
                 'name': body['name'],
-                'admin_ids': [(4, user.id)],
+                'admin_id': user.id,
             }
             if body.get('entityID'):
                 vals['entity_id'] = int(body['entityID'])
@@ -89,8 +89,8 @@ class ClassroomsController(EncoachMixin, http.Controller):
             if 'participants' in body:
                 vals['participant_ids'] = [(6, 0, [int(pid) for pid in body['participants']])]
 
-            if 'admins' in body:
-                vals['admin_ids'] = [(6, 0, [int(aid) for aid in body['admins']])]
+            if 'admins' in body and body['admins']:
+                vals['admin_id'] = int(body['admins'][0])
 
             if vals:
                 group.write(vals)