Hello, I recently completed a game and had the idea to add a "donation goal", where if X amount of donations are made, then I will add a new feature to the game. I'm wondering 1) if this is allowed and 2) what the best approach to this might be? The game is completely free-to-play, and I was considering just adding an image of the current goal progress in the description of the game (even though everyone would just have to trust that I am accurately tracking donations). I've seen more official donation goals around, but I'm not sure how to use those or if I can with a free-to-play game.