Fixed config dataset_name

src/config.cpp

@@ -10,6 +10,6 @@ namespace config {
     int n_io_threads = 1;
     size_t n_slots = 100;
 
-    string dataset_name = "data";
+    std::string dataset_name = "data";
 
 }

src/config.hpp

@@ -15,7 +15,7 @@ namespace config
     extern int n_io_threads;
     extern size_t n_slots;
 
-    extern string dataset_name;
+    extern std::string dataset_name;
 }
 
 #endif