fix: add empty migration script, to avoid test problems

src/wuttjamaican/db/alembic/versions/4d3696b894d5_empty_migration.py

@@ -0,0 +1,39 @@
+"""empty migration
+
+Revision ID: 4d3696b894d5
+Revises: b59a34266288
+Create Date: 2025-12-28 13:56:20.900043
+
+"""
+
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+import wuttjamaican.db.util
+
+
+# revision identifiers, used by Alembic.
+revision: str = "4d3696b894d5"
+down_revision: Union[str, None] = "b59a34266288"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+# NOTE: this empty revision exists simply to ensure that its down
+# revision (b59a34266288) is not the branch head.  and that is needed
+# because some of the tests in wuttaweb now run commands like these:
+#
+#     alembic downgrade wutta@-1
+#     alembic upgrade heads
+#
+# which is actually fine for postgres but not so for sqlite, due to
+# the particular contents of the b59a34266288 revision.
+
+
+def upgrade() -> None:
+    pass
+
+
+def downgrade() -> None:
+    pass