Database manager

@isupeene Working Database manager that is tested. Still needs contracts.

Note: Need to run database_clear.sql and then database_setup.sql on our DB before submitting.
Function gets the stats relevant to leaderboards from the Results table. It is basically a place to store the SQL relevant to gathering the win/loss/tie stats for players so that it can be displayed in the leaderboards in the clients. I guess this could instead be done through ruby after running get_results but I think the SQL option is probably better.