app.rb

  get '/' do
    session.clear
    erb :index
  end

  get '/play' do
    redirect '/' if session[:player_one_type].nil?
    player_first_move_check
    game = get_game
    @board = game.board
    @message = game.get_message(session[:player_first_move])
    redirect to '/play' if game.computer_move_check(@board, session[:current_board])
    erb :play
  end

  get '/difficulty' do
    erb :difficulty
  end