We need to improve the comments explaining the main ideas / insights of the solution

Regressed in DMOJ/judge-server#673, since now the cache is per-worker-process, and gets destroyed on exit. Will require a rewrite of the caching system.

Description

yukicoderに提出しようとするとエラーを吐くのでメッセージに従って更新しようとしたらうまくいかなかった

[INFO] load cookie from: /Users/beet/Library/Application Support/online-judge-tools/cookie.jar
[NETWORK] GET: https://yukicoder.me
[NETWORK] redirected to: https://yukicoder.me/
[NETWORK] 200 OK
[INFO] You are logged in.
[NETWORK] GET: https://yukicoder.me/problems/no/1269
[NETWORK] 200 OK
[INFO] both G

It would be great to add a subset of the now only jury available stats also to the team and public pages.

I'm thinking of the submission graph over time (but all rejected verdicts bundled into one, of course nothing after the freeze) and the total number of attempts/corrects.

There are two sets of refactoring that can be performed on our codebase to make them more efficient and utilize the full potential offered by Qt Framework. See below:

1. There is no need to explicitly call delete on widgets that are allocated on Heap as long as in their constructor we have specified the parent widget for it. Consider this example below:

class Widget: public QObject