diff --git a/src/Model/Factory.php b/src/Model/Factory.php
index ab560e3..34f589b 100644
--- a/src/Model/Factory.php
+++ b/src/Model/Factory.php
@@ -11,7 +11,7 @@ class Factory
     public $config;
     public $user;
 
-    public function __construct(Database $db, Registry $config = null, User $user = null)
+    public function __construct(Database $db, ?Registry $config = null, ?User $user = null)
     {
         $this->db = $db;
         $this->config = $config;