whitelist on website blocked doesnt work (#1452)

Since Pi-hole redirects ad domains to itself, accessing the script via de.ign.com is the same as pi.hole in this case. The fix should be as simple as adding a / before admin on this line.

advanced/index.php

@@ -185,7 +185,7 @@ function add() {
 	}
 
 	$.ajax({
-		url: "admin/scripts/pi-hole/php/add.php",
+		url: "/admin/scripts/pi-hole/php/add.php",
 		method: "post",
 		data: {"domain":domain.val(), "list":"white", "pw":pw.val()},
 		success: function(response) {