Implement a turn-based Tic Tac Toe game. Here are some requirements to get you started:
- Players take turns choosing squares until the game is over.
- A player can take any square that hasn't been chosen yet.
- The game is over when a player has three squares in a row, column, or diagonal.
- The game is over when there are no more squares to choose.
- X takes the first move.
Write all code, including specs, in tic_tac_toe.rb. Run the specs with rspec tic_tac_toe.rb.