A little gist showing how you could bind an app with an adapter to a web controller.

hexagon.rb

class Board
  def add_ship ship
    ship
  end

  def shoot(coordinates, player)
    raise "Not your turn" if player == 2
    'BANG'
  end
end

class GameInteractor
  def initialize
    @board = Board.new
  end

  def add_ship params, listener
    ship = @board.add_ship params[:ship][:name]
    listener.ship_added(ship)
  end

  def shoot coordinates, player, listener
    begin
      @board.shoot(coordinates, player)
      listener.shot_at coordinates
    rescue Exception => e
      listener.not_his_turn player, e.message
    end
  end
end

class Sinatra
  def initialize
    @game = GameInteractor.new
  end

  def add_ship params
    @game.add_ship(params, self)
  end

  def shoot coordinates, player
    @game.shoot coordinates, player, self
  end
  
  def ship_added ship
    "That's awesome, thank you!"
  end

  def shot_at coordinates
    "You have shot at #{coordinates}"
  end

  def not_his_turn player, message
    "Hey #{player}! #{message}"
  end
end