def incr(key, count=1)
      @store.transaction do
        unless @store[key].nil?
          @store[key] = @store[key] + count
        else
          @store[key] = count
        end
      end
    end
def incr(key, count=1)
      @store.transaction do
        unless @store[key].nil?
          @store[key] = @store[key] + count
        else
          @store[key] = count
        end
      end
    end
increment key by count