def put(key, item)
      if @items.include?(key)
        delete(key)
      end
      if @list.size == @max_count
        delete(@list.first)
      end
      @items[key] = item
      @list.push(key)
      item
    end
def put(key, item)
      if @items.include?(key)
        delete(key)
      end
      if @list.size == @max_count
        delete(@list.first)
      end
      @items[key] = item
      @list.push(key)
      item
    end
Initialize cache
 Add item to cache