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That's a good note about number keys for the tools 1-4 would do it.

Unfortunately, for the leader boards I literally made a function in Microsoft Azure and used Azure Data Tables to store the data. That's what it takes if you're going to save people's solutions the way I did.

There is a free and easy leaderboard solution through Microsoft though I think it's gone through some changes since I last used it.

Playfab: https://developer.playfab.com/en-us/sign-up