guess.rb

 match(/guess (\S+)/, method: :guess)
  def guess(m, guessed_word)
    result = @game.guess(guessed_word)
    
    reply = case result
    when :missed_north
      "My word comes after #{guessed_word}."
    when :missed_south
      "My word comes before #{guessed_word}."
    when :correct
      "#{m.user}: congratulations, that's the word! You win!"
    when :not_a_word
      "#{m.user}: sorry, #{guessed_word} isn't a word. At least, as far as I know"
    when :no_game
      "You haven't started a game yet. Use `!word start` to do that."
    end
    
    m.reply reply
  end