Switch to drogon

src/update_handler.hpp

@@ -8,7 +8,7 @@ namespace simple_object_storage {
 class UpdateHandler {
 public:
     explicit UpdateHandler(Server& server);
-    void handle_update_object(const httplib::Request& req, httplib::Response& res);
+    void handle_update_object(const drogon::HttpRequestPtr& req, std::function<void(const drogon::HttpResponsePtr &)>&& callback);
 private:
     Server& server_;
 };