Improve README.md a little bit

README.md

@@ -1,5 +1,69 @@
 # jukebox
 
+**Note**: This generates the schedule for Frikanalen v3, currently running on [beta.frikanalen.no]().
+Until v2 is decommissioned, schedule is still generated by [these scripts](https://github.com/Frikanalen/frikanalen/tree/master/packages/fkweb/agenda/management/commands), invoked by [these cron jobs](https://github.com/Frikanalen/frikanalen/tree/master/infra/k8s/django/periodic-schedule-tasks). 
+
 ![Coverage](https://raw.githubusercontent.com/Frikanalen/jukebox/main/badges/coverage-jest%20coverage.svg)
 
-This automatically schedules videos on the Frikanalen linear schedule.
+This schedules videos on the Frikanalen linear schedule.
+
+It weights candidates videos according to various criteria, like so:
+
+```typescript
+  const entries = fillPeriod(startAt, endAt, {
+    weightings: [
+      { criteria: "notRecentlySeenFromSameOrganization", multiplier: 100 },
+      { criteria: "notScheduled", multiplier: 30 },
+      { criteria: "notRecentlySeen", multiplier: 20 },
+      { criteria: "notSeenThisWeek", multiplier: 10 },
+      { criteria: "notSeenToday", multiplier: 10 },
+      { criteria: "isRecent", multiplier: 2 },
+      { criteria: "rand", multiplier: 1 },
+    ],
+    videos,
+  })
+```
+
+To get to an MVP of Frikanalen v3.0 as soon as possible while retaining flexibility for future 
+support for eg. live events, the schedule is split into multiple layers.
+
+The previous generation of software had limited to no support for live events, and in migrations the schedule is copied directly into the jukebox table.
+
+The jukebox generates the "background layer", currently the only one in the database.
+
+In the future, user-scheduled videos and live events will occupy other database tables, which will then override whatever is defined by the jukebox.
+
+## Requirements / configuration
+
+Set the environment variable FK_API_KEY to the same value as seen by toches, and set `FK_API` to an URL pointing to it. 
+
+Copy dev-env to .env for standard defaults for development.
+
+## Cron job
+
+```yaml
+apiVersion: batch/v1
+kind: CronJob
+metadata:
+  name: jukebox
+  namespace: beta
+spec:
+  jobTemplate:
+    spec:
+      template:
+        spec:
+          containers:
+          - env:
+            - name: FK_API
+              value: https://beta.frikanalen.no/api/v2
+            - name: FK_API_KEY
+              valueFrom:
+                secretKeyRef:
+                  key: FK_API_KEY
+                  name: fk-api-key
+            image: frikanalen/jukebox-v2:latest
+            name: jukebox
+  schedule: 00 22 * * *
+  successfulJobsHistoryLimit: 3
+  suspend: false
+```