managers in migrations

django.diff

diff --git a/django/db/migrations/state.py b/django/db/migrations/state.py
index b1cba07..1fdd9f6 100644
--- a/django/db/migrations/state.py
+++ b/django/db/migrations/state.py
@@ -467,7 +467,10 @@ class ModelState(object):
                 (name, instance) for name, (cc, instance) in
                 sorted(managers_mapping.items(), key=lambda v: v[1])
             ]
-            if managers == [(default_manager_name, models.Manager())]:
+            # In case the only manager on the model is the default manager
+            # defined by Django (objects = models.Manager()) migrations won't
+            # add that manager to the model state.
+            if managers == [('objects', models.Manager())]:
                 managers = []
         else:
             managers = []