+from django.core.management import setup_environ
+import settings
+
+setup_environ(settings)
+
+from catalogue.models import Tag, Book
+from django.db import connection
+
+query = 'ALTER TABLE catalogue_tag ADD COLUMN book_count integer NOT NULL DEFAULT 0'
+
+cursor = connection.cursor()
+cursor.execute(query)
+
+for shelf in Tag.objects.filter(category='set'):
+ shelf.book_count = len(Book.tagged.with_all(shelf))
+ shelf.save()