central_perk_create_order.rb

# From this...
def create
  @order = Order.create(order_params)
  if @order.save
    redirect_to order_path(@order)
  else
    render :new
  end
end

# To this...
 def create
  @order = Order.create(order_params)

  items_to_add = params[:order][:menu_item_ids]

  items_to_add.each do |item_id|
    if item_id != ""
      item_id = item_id.to_i
      item_to_add = MenuItem.find_by_id(item_id)
      @order.menu_items << item_to_add
    end
  end

  if @order.save
    redirect_to order_path(@order)
  else
    render :new
  end

end