Guessing Game implemented in Ruby

GuessingGame.rb

class GuessingGame  
  def initialize
    @upper_limit=100
    @lower_limit=1
    @guess=50
    @quit = false
    until self.quit_playing
      self.comp_guess
      self.input = gets.chomp.to_i
    end
  end

  def guess_number
    ((@upper_limit + @lower_limit)/2)
  end
  
  def too_low
    @lower_limit = @guess
  end
  
  def too_high
    @upper_limit = @guess
  end
  
  def input=(player_input)
    case player_input
    when 1
      self.too_low
    when 2
      self.too_high
    when 3
      self.win
    else
      puts "Please pick option 1, 2, or 3."
    end

    @guess = self.guess_number
  end
  
  def win
    @quit = true
    puts "\n\nYou win!!\nThanks for playing!\n\n"
  end
  
  def comp_guess
    puts "\n\nPlease select one of the following:\n(1) Too Low\n(2) Too High\n(3) That's it!\n\nI guess #{@guess}"
  end
  
  def quit_playing
    @quit
  end
end

This_Game = GuessingGame.new