Lets digest-service.ts know when each user's next digest is due.
digest_schedule holds, for each user and cadence they receive, the start
of the period their next digest covers; it is due once a full period has
passed.
f
up(db: DatabaseSync): void
Run once by runMigrations. Every user present gets both cadences, with a
first period that ends at some hour of the coming week or month, picked
from their id: the digests start trickling out after the deploy instead of
all leaving a week later. Users created later are scheduled by the service
when it first sees them.
Usage
import * as mod from "api/db/migrations/0020_digest_schedule.ts";