Remove user's submitions when delete problem

[behitek]

Hi you guy,
I'm using your version with some of my custom for my student study (may be useful for you):

• Allow sort problem by AC rate/ solved (BE + FE)
• [Fix] Two Factor Authen error b/c compare case insensitive (FE)
• Use a tag to improve SEO, can open problem in newtab (FE)

But, when use in production, I found some issues:

• User score not change when delete proble.
• User home not list all AC problem.
• Problem tags case insensitive.
• Userhome display wrong list of AC problems.

Can you guy tell me some hints: How/where (in this repo) to fix these problems. I also want to contribute to this awesome project!
Thanks.