Remove default admin user name from config

config.default.php

@@ -59,9 +59,12 @@ $require_authentication = 1;
 // (0 = no, 1 = yes)
 $public_tracks = 0;
 
-// admin user who has access to all users locations
+// admin user, who
+// - can add new users
+// - can edit all tracks, users
+// - has access to all users locations,
 // none if empty
-$admin_user = "admin";
+$admin_user = "";
 
 // miniumum required length of user password
 $pass_lenmin = 12;