Use `ioredis`

[kylemclaren]

This PR introduces a breaking change and replaces @upstash/redis with ioredis so that we can deploy the full stack on Fly. Upstash for Redis® on Fly.io uses a unified redis connection string for direct DB connections — not the REST API.

Now, instead of setting UPSTASH_REDIS_REST_URL and UPSTASH_REDIS_REST_TOKEN, we set a single REDIS_URL env var which looks like redis://[email protected]

[enesakar]

hey @kylemclaren have you checked the redis methods? I see you have not changed any method, so the new client is compatible with old one?

[kylemclaren]

@enesakar sorry I was OoO — I did briefly check the methods and they looked directly compatible. I left this in draft as I didn't have a chance to test it. Will try get to it this week!