Option to upload an editorial for a contest

[ThanakritW]

Not an issue, more like a suggestion.
Not sure if it will be practical, but if we add some kind of a button which will lead to an editorial of that contest here...

and here...

Pros:

• Editorial will always exist there, so might be beneficial for ppl who are trying to learn.
• No editorial will get lost in time.
• Ensuring that anyone who has competed in the contest will find the editorial in the problem they couldn't solve.

Cons:

• Unintentional spoiler for problems that are currently closing.
• If problem in the contests are overlapped, someone might used the code in the old editorial to answer that
• Not all contest has editorial
• Anos Posidos might be too lazy to implement this :P