feat(backend): test cases migration

backend/alembic/versions/003_add_test_cases.py

@@ -0,0 +1,34 @@
+"""add test cases
+
+Revision ID: 003
+Revises: 11f3a598b82d
+Create Date: 2025-04-12
+
+"""
+
+from collections.abc import Sequence
+
+import sqlalchemy as sa
+from alembic import op
+from sqlalchemy.dialects import postgresql
+
+revision: str = "003"
+down_revision: str | None = "11f3a598b82d"
+branch_labels: str | Sequence[str] | None = None
+depends_on: str | Sequence[str] | None = None
+
+
+def upgrade() -> None:
+    op.add_column(
+        "questions",
+        sa.Column("function_signature", sa.Text(), nullable=True),
+    )
+    op.add_column(
+        "questions",
+        sa.Column("test_cases", postgresql.JSONB(astext_type=sa.Text()), nullable=True),
+    )
+
+
+def downgrade() -> None:
+    op.drop_column("questions", "test_cases")
+    op.drop_column("questions", "function_signature")