reference the config file without relying on working directory

cron/tests.php

@@ -1,6 +1,6 @@
 <?php
 // Cron job started every 15 minutes - up/down checks
-require_once('../common_config.php');
+require_once(__DIR__.'/../common_config.php');
 try{
 	$db=new PDO('mysql:host=' . DBHOST . ';dbname=' . DBNAME, DBUSER, DBPASS, [PDO::ATTR_ERRMODE=>PDO::ERRMODE_WARNING, PDO::ATTR_PERSISTENT=>PERSISTENT]);
 }catch(PDOException $e){