public static void main(String[] args) {
        TicTacToe game = new TicTacToe();

        System.out.println("Welcome to TicTacToe!\n");

        game.setMark(5);
        game.newBoard();


        while (!game.isQuitGame()) {
            System.out.println("\nWhat do you want to do?");
            System.out.println("1. Play a game of TicTacToe");
            System.out.println("2. See rulebook");
            System.out.println("3. Quit\n");

            //Get user input
            boolean validInput = false;
            int userInput = -1;
            while (!validInput) {
                userInput = game.getUserInput();
                if (userInput == -1 || userInput < 1 || userInput > 3)
                    System.out.println("Please select a number between 1 and 3");
                else
                    validInput = true;
            }

            if (userInput == 1) {
                //Play game
                game.playGame();
            } else if (userInput == 2) {
                //Print rulebook
                System.out.println("\nRULES:");
                System.out.println("\nThe board looks like this:\n");

                System.out.println("[1 2 3]");
                System.out.println("[4 5 6]");
                System.out.println("[7 8 9]\n");

                System.out.println("Player 1 writes X's, player 2 writes O's.");
                System.out.println("When it's your turn, press a number from 1 to 9 to mark the corresponding field.");
                System.out.println("The first one to get three fields in a row wins!\n");
            } else if (userInput == 3) {
                //Quit game
                game.quitGame();
            }
        }

        System.out.println("\n Have a nice day!");
    }