Add migration to set installed version in config

migrations/v308/add_version.php

@@ -0,0 +1,18 @@
+<?php
+
+namespace mober\discordnotifications\migrations\v308;
+
+class add_version extends \phpbb\db\migration\migration
+{
+	static public function depends_on()
+	{
+		return ['\mober\discordnotifications\migrations\extension_installation'];
+	}
+
+	public function update_data()
+	{
+		return [
+			['config.add', ['discord_notification_version', '3.0.8']],
+		];
+	}
+}