There should be a doc detailing how the bot is set up (source location, Heroku settings, etc.) so if all the devs disappear it's straightforward to get it up and running again.

When I tried to link my lichess account, the belt check correctly failed because I didn't have a stable classical rating, but it should be still be linked in my profile. Instead, my !profile results include lichess username: None. Presumably the same is true for chess.com.

BotTrosian needs to remember who users in discord are, and know when they've linked chess.com or lichess.org accounts.

Database needs to be able to store:

• Authenticated users
• Linked chess.com profiles
• Linked lichess.org profiles
• Yesterday's elo
• Today's elo

Schema things

Authenticated Users

• DiscordID primary key VARCHAR(63)
• DojoBelt VARCHAR(63)
• ModAwardedBelt VARCHAR(63)

Lichess Data

• DiscordID foreign key VARCHAR(63)
• lichess username primary key VARCHAR(255)
• Most recent lichess classical elo SMALLINT
• Yesterday's lichess classical elo SMALLINT

Chess.com Data

• DiscordID foreign key VARCHAR(63)
• Chess.com username primary key VARCHAR(255)
• Most Recent Chess.com rapid elo SMALLINT
• Yesterday's Chess.com rapid elo SMALLINT

Note: I have no idea how to do database migrations in Heroku Postgres, and there's a chance I'll have to do some database stuff by hand if this needs to be updated later.

Schema Rationale

If I want to get fancy at some point, I can probably enforce in the database that a DiscordID in the authenticated user list has at least one of lichess data, chess.com, and I can definitely enforce with this schema that if a DiscordID is deleted (which is not currently supported or roadmapped functionality) it will delete the linked profiles in a cascading way.

Making usernames a primary key ensures that two users don't grab the same profile somehow. This might not be necessary, so maybe I shouldn't enforce this.

SMALLINT supports ELOs well above 3600 which isn't really a human elo.

Storing data in site-specific tables will make it easier to add database support for other sites later if desired. This also makes daily updates pretty easy, since we'll just need to update all the data in the two site-specific tables, and then update all the belts in authenticated users.

Discord or discord.py appear to have some concept of "guild", and those might be relevant to this bot's effective operation. I should learn what these are!

The comparison of the chess.com location / lichess bio field with the Discord ID should be case-insensitive.

Given a discord message with a FEN such as:
r1bqkbnr/pp1ppppp/2n5/2p5/4P3/5N2/PPPPKPPP/RNBQ1B1R b kq - 3 3

bottrosian should be able to generate a png and post it in the linked discord