Added more user and system events

app/Bus/Events/System/SystemWasInstalledEvent.php

@@ -0,0 +1,22 @@
+<?php
+
+/*
+ * This file is part of Cachet.
+ *
+ * (c) Alt Three Services Limited
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace CachetHQ\Cachet\Bus\Events\System;
+
+/**
+ * This is the system was installed event class.
+ *
+ * @author James Brooks <james@alt-three.com>
+ */
+final class SystemWasInstalledEvent implements SystemEventInterface
+{
+    //
+}