Create Decorators

* Match will show different elo depending on completeness
* Match completed shows elo of the time
* Match incompleted shows player's elo
If we have a Match A, the elo's of the players involved with Match A could vary depending if they played other matches. So while the match is incomplete, Match A should show the most current Elo of the players. This Elo is also used to calculate the new Elo of each player. However, when the Match is completed, the match history should show the Elo of the players at the time when the match is completed which is `defender_elo` and  challenger_elo`