There is an Achievement which gives you a Black Rook once you have used (bought) all bonus code colors.
Question: does it also apply if the buys are for other players?
So, could I buy some one a rook for a year with the yellow bonus, later buy a rook for a year for someone else for a year with the red bonus, etc. and get the Black Rook for it? Or do I need to buy all those rooks for myself to get the achievement?