Suggestion: Private (or Friends-Only) Fastest Solvers lists

[universalset]

One neat thing that Advent of Code does is to allow users to organize private leaderboards, so that they can have an informal competition with their friends even if they are not fast enough (or not awake at the right time) to compete globally.

I suspect it would be a fun feature for newer users solving older problems, and/or users with groups of friends who are not all strong enough to get onto the public global fastest-solvers lists, to have the ability to view fastest solvers filtered to show only users in a small private-leaderboard-group (instead of to top 100), or to show users only in their friends list. (Possibly there could even be a private leaderboard page analogous to the Eulerians ranking too.)

I'm not sure how the database is set up and how fastest solvers are dealt with now, so possibly it would be too expensive or not feasible to set something like this up. But if it's not going to be rough on the infra, I think it would be a cool addition.

[euler]

It certainly is a nice idea. I'll look into this idea over the summer break and do some testing to see how intensive the process is on the server. It could be a problem if some members start trying to scrape the data for multiple problems, but I have thoughts on how to prevent that.