This will migrate Mantaro's RethinkDB database store to MongoDB. Use this only if you're migrating from version < 8.0 to 8.0 or higher (master branch)
Make sure to set the MIGRATOR_MONGO_URI, MIGRATOR_RETHINK_HOST, MIGRATOR_RETHINK_USER and MIGRATOR_RETHINK_PW (last two can be empty for defaults) environment variables. It should do the job by itself and let you know when it's done, assuming you set the database hosts/uri correctly.