Buttondown no longer runs Redis

Buttondown no longer runs Redis! I added it years ago for the same reason almost every Django app has Redis: that's just what you do. Workers wanted a queue, the queue wanted a broker, the broker was Redis. The cache wanted a backend, the backend was Redis. Sessions wanted a store, the store was Redis. And then it festers from there. 1Though "festers" is unkind: I have no qualms with Redis as a technology, I just have qualms with twice as many datastores as I ought to have. I wrote earlier this year about pulling django-rq and the worker queue off of Redis. What was left after that was mostly small: rate-limit counters, a few short-TTL caches, an idempotency-key fast-path, and session storage. Not enough to really cause any issues, but we're working on our Heroku migration 2Stay tuned for more., and big infrastructural changes are made slightly easier by one fewer dependency, even if it's a fairly static one. When I actually measured the replacements against production Postgres, they…