Make first Alembic migration idempotent for existing databases

Production DB already has refresh_schedule and last_refreshed_at columns
(created with the initial table). The migration now checks for column
existence before adding, so alembic upgrade head works on both fresh
and existing databases.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: mrwind-up-bird

alembic/versions/c8b5dd2aff5e_add_refresh_schedule_and_last_refreshed_.py

@@ -19,8 +19,13 @@
 
 
 def upgrade() -> None:
-    op.add_column("sources", sa.Column("refresh_schedule", sa.String(20), nullable=True))
-    op.add_column("sources", sa.Column("last_refreshed_at", sa.DateTime(), nullable=True))
+    conn = op.get_bind()
+    inspector = sa.inspect(conn)
+    columns = {c["name"] for c in inspector.get_columns("sources")}
+    if "refresh_schedule" not in columns:
+        op.add_column("sources", sa.Column("refresh_schedule", sa.String(20), nullable=True))
+    if "last_refreshed_at" not in columns:
+        op.add_column("sources", sa.Column("last_refreshed_at", sa.DateTime(), nullable=True))
 
 
 def downgrade() -> None: