async up(db, client) {
    // TODO write your migration here.
    // See https://github.com/seppevs/migrate-mongo/#creating-a-new-migration-script
    // Example:
    // await db.collection('albums').updateOne({artist: 'The Beatles'}, {$set: {blacklisted: true}});
  }
@param db {import('mongodb').Db}
@param client {import('mongodb').MongoClient}
@returns {Promise<void>}