Fix #238: migration to backport prod index

migrations/versions/20241001_8433b007b38a_index_backport.py

@@ -0,0 +1,30 @@
+"""Create index on lowercase primary emails
+
+Revision ID: 8433b007b38a
+Revises: 3689b813fe22
+Create Date: 2024-10-01 18:46:43.405004
+
+"""
+# pylint: disable=no-member invalid-name
+# no-member is triggered by alembic.op, which has dynamically added functions
+# invalid-name is triggered by migration file names with a date prefix
+# invalid-name is triggered by top-level alembic constants like revision instead of REVISION
+
+import sqlalchemy as sa
+from alembic import op
+
+# revision identifiers, used by Alembic.
+revision = "8433b007b38a"  # pragma: allowlist secret
+down_revision = "3689b813fe22"  # pragma: allowlist secret
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    op.execute(
+        """CREATE UNIQUE INDEX IF NOT EXISTS idx_email_primary_unique_email_lower ON public.emails USING btree (lower((primary_email)::text));"""
+    )
+
+
+def downgrade():
+    op.execute("""DROP INDEX IF EXISTS idx_email_primary_unique_email_lower;""")