Shopping cart (Newbie)

I have a shopping cart project that I am putting together. I am able
to combine items and get the correct price, however the quantity does
not show up as to how many of the same item is being bought. Here is
my code. Any suggestions wold help out this newbie... not sure what I
am doing wrong...Thanks!

class Basket

  attr_reader :purchases
  attr_reader :total

  def initialize
  @purchases = []
  @total = 0.0
  end

   def add_purchase(cart)
    @purchases << Purchase.buy_one(cart)
  @total += cart.price
  end

   def add_purchase(cart)
     appendFlag = true
     for purchase in @purchases
       if (cart.id == purchase.cart.id)
        appendFlag = false
         purchase.quantity += 1
        end
     end
   if(appendFlag)
   @purchases << Purchase.buy_one(cart)
   end

  @total += cart.price
  end

   def clear
        @purchases = []
        @total = 0.0
        end

end