Add a migration for backfilling user UUIDs.

data/migrations/versions/1c5b738283a5_backfill_user_uuids.py

@@ -0,0 +1,23 @@
+"""backfill user uuids
+
+Revision ID: 1c5b738283a5
+Revises: 2fb36d4be80d
+Create Date: 2014-11-20 18:22:03.418215
+
+"""
+
+# revision identifiers, used by Alembic.
+revision = '1c5b738283a5'
+down_revision = '2fb36d4be80d'
+
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.dialects import mysql
+from util.backfill_user_uuids import backfill_user_uuids
+
+def upgrade(tables):
+  backfill_user_uuids()
+
+
+def downgrade(tables):
+  pass