Bot running out of memory

[EndBug]

As the bot is added to more and more servers, discord.js is starting to cache so much data that it exceeds the memory limit.
This problem is, as of now, not going to be fixed, since discord.js relies pretty heavily on internal caching and won't work without it. For more info about that, check discordjs/discord.js#1409

These are the current possible solutions for the bot:

• Deploy it to a server which has a lot more RAM: this would be both expensive and ineffective in the long term, since the bot could eventually use up more memory.
• Use sharding and deploy the bot to multiple Heroku instances: this might work, but it would require some work to implement sharding and, considering how the bot works, may not be the best option. Eventually, if the bot approaches ~1000 guilds, it's something that I'll need to do anyway, but I think I'll procrastinate till then.
• Easiest solution: make the bot reboot periodically. This will "manually" clear the cache, and it's the quickest way to solve the problem for now.

[EndBug]

The bot should now restart every 24 hours. I'll close this issue, for now, I'll reopen it if necessary.