Create NodeJS Worker for Discord Communication

[crutchcorn]

As we're looking to add Discord communication to our server to do SSR, we need to:

• Add env vars: https://github.com/playfulprogramming/playfulprogramming/pull/1241/files#diff-a3046da0d15a27e89f2afe639b25748a7ad4d9290af3e7b1b6c1a5533c8f0a8c
• Add discord.js package
• Add socket.io connection to open comms
• Prevent anybody from connecting to this socket.io connection, only our SSR

Related code: playfulprogramming/playfulprogramming#1241
Related issue: #3

[fennifith]

Need to decide if this should be event-driven or not (e.g. if we want new messages shown immediately, or to be updated after a delay)

Possible solution, if this is event-driven:

• "discord bot" package that runs as its own Fly service (to only run one machine at a time)
• Runs a websocket server that accepts connections directly from astro/SSR
• Keep track of recent messages for each channel in-memory
• When a message is received, update recent messages and send a message to each socket connection
• When a new client connects (e.g. if astro SSR is restarted), resend all stored messages
• Frontend: when the websocket connection receives new messages, store them and use for any future SSR renders

If this is not event-driven:

• Create a worker task that intermittently imports recent messages into the db
• Create a GET /discord/[channel]/recent_messages endpoint to retrieve those messages
• Frontend: call the recent_messages endpoint and cache the results between SSR renders

[crutchcorn]

IMO this shouldn't be event driven