compare rank algorithm
- (0, 1000] rookie
- (1000, 1500] bronze
- (1500,2000] silver
- (2000,2500] gold
- (2500, 3000] platium
- (3000,3500] diamond
- (3500, 4000] master
- (4000,inf) grandmaster
- Season 0: when season begin, every player's rankPoints are 500
- Season 1: when season begin, every player's rankPoints are talent - 1000, the minimum is 0
talent: talent score, readonly
rankPoints: current score
recordX: Results of the first X matches
record: Results of all matches
winRateX: win rate of the first X matches
winRate: win rate of all matches
observed: the player is observed or not