Keep statistics of finished games

[Tomin1]

Currently there is no record of finished games. It would be possible to save finished games (lost and won) to sqlite database and then calculate statistics (number of games played and won, time) to display. Player finishing a game and then undoing a move should be also carefully considered when collecting the statistics. This also needs some UI design for another page in the application. There are also some performance considerations once the number of played games grows very large.