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.
I had auto-incrementing ID but thought an auto-incrementing id didn't make the most sense with the other functions that we had specified in the contract such as load_game(id). I can change it to AUTO_INCREMNENT though and just return the ID. Also changed ID cause I thought ids should be the same between results and saved_games but now I realize that isn't the case because we could have multiple saves of the same game that will all have different ids in the results table.

TL;DR I'll change them to auto_increment