Method add

src/Server/APIRequestHandler.h:31–34

        template <class K, class V>
        void add(K && k, V && v)
        {
            doc.AddMember(std::forward<K>(k), std::forward<V>(v), doc.GetAllocator());
        }

        template <class K>
        void add(K && k, const std::string & v)