Added some headers

Backend/Controllers/FileHandler/GetGameData.php

@@ -14,6 +14,7 @@ if(isset($_GET['gameDataId'])){
     $openGameDataStream = GameData::all();
 }
 
-
+header("Access-Control-Allow-Methods: GET");
+header("Access-Control-Allow-Headers: X-Requested-With, Content-Type, Accept");
 header('Content-Type: application/json;charset=UTF-8');
 echo $openGameDataStream->toJson(JSON_PRETTY_PRINT);