feature: plugin cronjobs (#215)

system/bin/cronjob.php

@@ -0,0 +1,19 @@
+<?php
+
+require_once __DIR__ . '/../../common.php';
+require_once SYSTEM . 'functions.php';
+require_once SYSTEM . 'init.php';
+require_once SYSTEM . 'hooks.php';
+
+$hooks = new Hooks();
+$hooks->load();
+
+use GO\Scheduler;
+
+// Create a new scheduler
+$scheduler = new Scheduler();
+
+$hooks->trigger(HOOK_CRONJOB, ['scheduler' => $scheduler]);
+
+// Let the scheduler execute jobs which are due.
+$scheduler->run();