Add tests

# Unit tests

## Speedrun.com related
- [x] categories_played
- [x] games
- [x] posts
- [x] runs_count
- [x] whois
- [x] world_records
- [ ] categories
- [ ] category_info
- [ ] game_info
- [ ] leaderboard
- [ ] level_info
- [ ] mod_count
- [ ] podiums
- [ ] run_info
- [ ] runs
- [ ] world_record

### Utils
- [ ] fmt.ts
- [ ] utils.ts (possibly test this as well, not sure)

# Integration tests

## API
- [ ] All

## Frontend
(kinda nonexistent at the moment)
- [ ] All

## Discord
- [ ] /categories-played
- [ ] /games
- [ ] /posts
- [ ] /runs-count
- [ ] /whois
- [ ] /world-records
- [ ] /categories
- [ ] /category-info
- [ ] /game-info
- [ ] /leaderboard
- [ ] /level-info
- [ ] /mod-count
- [ ] /podiums
- [ ] /run-info
- [ ] /runs
- [ ] /world-record

# Additional notes

Testing against speedrun.com is tricky. The site goes down a lot and the data changes a lot due to it's nature. I am not sure what the best way of testing stuff is. Maybe with a banned user such as `7H3` or with a mildly inactive user such as `1`. Testing against leaderboards (for leaderboard or world_record) it's tricky as well, so I am not sure what the best way to do it is.

Nontheless it would be a good idea to have a general idea if something goes wrong somewhere