Database Migration

Create a new reversible database migration.

Steps

1. Determine next migration number from backend/migrations/
2. Create backend/migrations/TIMESTAMP_description.ts
3. Follow the migration template
4. Implement both up() and down() functions
5. Test rollback: run npm run migrate:down then npm run migrate:up

See conventions.md for naming and patterns.

Arguments: $ARGUMENTS — description of what the migration does