Add tip regarding services

modules/concepts/services/_index.md

@@ -117,6 +117,18 @@ If you need more details about dependency injection and how services work in the
 their documentation about the [Service Container](https://symfony.com/doc/4.4/service_container.html).
 {{% /notice %}}
 
+##### Exclude index.php files when adding wildcard resource
+
+When adding resources with a wildcard to your module namespace, make sure to exclude all `index.php` files (this file is used for security; it is redirecting to FO to prevent reading from the directory). If you don't do it, you might be redirected whenever you open your shop.
+
+```yaml
+  your_company.your_module:
+    resource: '../src/*'
+    exclude:
+      - '../src/index.php'
+      - '../src/*/index.php' 
+```
+
 ### Override an existing Symfony service
 
 The container definition can be modified by a module, which enables you to override an existing Symfony service being used in PrestaShop.