/// Index a document.
bool ElasticSearch::index(const std::string& index, const std::string& type, const std::string& id, const Json::Object& jData){

    if(_readOnly)
        return false;

    std::stringstream url;
    url << index << "/" << type << "/" << id;

    std::stringstream data;
    data << jData;

    Json::Object result;
    _http.put(url.str().c_str(), data.str().c_str(), &result);

    if(!result.member("created"))
        EXCEPTION("The index induces error.");

    if(result.getValue("created"))
        return true;

    std::cout << "endPoint: " << index << "/" << type << "/" << id << std::endl;
    std::cout << "jData" << jData.pretty() << std::endl;
    std::cout << "result" << result.pretty() << std::endl;

    EXCEPTION("The index returns ok: false.");
    return false;
}