text: ALTER TABLE playlist
    ADD code VARCHAR(32) DEFAULT 'default' NOT NULL;
  CREATE UNIQUE INDEX playlist_owner_id_guild_id_code_uindex
    ON playlist (owner_id, guild_id, code);
  CREATE INDEX playlist_owner_id_code_index
    ON playlist (owner_id, code);
  CREATE INDEX playlist_guild_id_code_index
    ON playlist (guild_id, code);