diff --git a/alembic/versions/d7589827abbb_add_support_for_allow_rebase.py b/alembic/versions/d7589827abbb_add_support_for_allow_rebase.py
index f2382f5..c96bc26 100644
--- a/alembic/versions/d7589827abbb_add_support_for_allow_rebase.py
+++ b/alembic/versions/d7589827abbb_add_support_for_allow_rebase.py
@@ -24,7 +24,7 @@ def upgrade():
     )
     op.execute('''UPDATE pull_requests SET allow_rebase=False;''')
     op.alter_column(
-        'pull_requests', 'allow_rebase',
+        'pull_requests', 'allow_rebase', existing_type=sa.Boolean,
         nullable=False, existing_nullable=True)