Secondary currency

[Dinocanid]

This has been asked a few times in the past, but I couldn't find an answer for it. I tried doing it myself by going through each of the php files and duplicating and editing lines of code so there are two currencies. (I basically went around copy-pasting lines and renaming things to money2, cost2, etc.)
This didn't work, and I have no idea what to do. I tried going into phpMyAdmin to add another column to settings, but _settings can't be edited. I was trying to make a secondary currency that is harder to get and can be used to buy special adopts and items from a shop.

[LUC1G07CH1]

I'm also trying to do a premium currency...