#1 [harolei] Wrote the test and implement of printing the map of the game, and try to refactor it.
#2 [harolei] Wrote the test and the implement of displaying the position of the gamer on the map.
#3 [harolei] Wrote the test and the implement of changing the owner of the land after the land has been sold, and refactored the test.
#4 [harolei] Wrote the test and the implement of refreshing the map when gamer leave the current land and keep going.