Gives playlists categories of their own, a set apart from the dumps': each
category gets a kind, dump or playlist, its slug and name now unique
within its kind only, and playlist_categories files playlists under them.
/playlists becomes the page of every public playlist, so its first segment
is reserved.
f
up(db: DatabaseSync): void
Run once by runMigrations. Every existing category becomes a dump
category, filing the same dumps.
Usage
import * as mod from "api/db/migrations/0025_playlist_categories.ts";