Import taggit.managers in 0045_migrate_tags.py
@@ -8,6 +8,7 @@ from django.core import serializers
from TWLight.resources.models import TextFieldTag, Partner
from taggit.models import Tag, TaggedItem
+import taggit.managers
# Migrate the existing tag objects to the model that lives in resources.
def copy_tags(apps, schema_editor):
