Add the initial version of 2048 game engine.
Init game board with two random numbers.
Rename game2048 -> text2048.
Bundle rubocop.
Bundle cucumber and aruba.
Guard.
Refactor.
Curses UI.
Delete destructive methods.
Add score.
Add frame lines.
Do not generate a number if numbers didn't move.
Fix rubocop warnings.
Refactor.
Fix generate bug.
Quit a game with 'q'.
Refactor.
Refactor.
Refresh on each #draw_tile.
Refactor.