updated guide

docs/README.md

@@ -5,3 +5,8 @@ Getting Started
 ---------------
 
 - [Installation](installation.md)
+
+Guides
+------
+
+- [Using custom auth manager](using-custom-auth-manager.md)

docs/using-custom-auth-manager.md

@@ -0,0 +1,36 @@
+Using custom auth manager
+=========================
+
+Yii2-rbac provides special database auth manager that extends default manager provided by Yii. However in some projects
+you may need to override in order to add some features that you need. Or you may want to use php files instead of database
+to store auth data. In this case your class should implement interface `dektrium\rbac\components\ManagerInterface`:
+
+```php
+
+namespace app\components;
+
+class MyManager extends \yii\rbac\PhpManager implements \dektrium\rbac\components\ManagerInterface
+{
+    public function getItems($type = null, $excludeItems = [])
+    {
+        // you should implement this method or extend your class from \dektrium\rbac\components\DbManager
+    }
+
+    public function getItem($name)
+    {
+        // you should implement this method or extend your class from \dektrium\rbac\components\DbManager
+    }
+}
+```
+
+After you created your class you should add it to your config file:
+
+```php
+[
+    'components' => [
+        'authManager' => [
+            'class' => 'app\components\MyManager',
+        ],
+    ],
+]
+```