Feature Request: Unlock Training up to Current Rank

[alexjdw]

Hi! I'm ~4k on everything in the app but in order to do all of the topics at 4k level, I have to do thousands of 15k and 10k puzzles. We need a feature that unlocks all of the trainings up to a certain rank, otherwise it's close to unusable for advanced players.

[alexjdw]

(I can do a PR if that's acceptable)

[ale64bit]

(I can do a PR if that's acceptable)

It's very acceptable! But maybe let's discuss a bit. Should this be a specific rank selected by the user or use some other measure indirectly? (like the highest grading exam rank, for example). Consider joining our Discord server to check with other members as well.