Fix concepts.md

Author: paulbalandan

docs/concepts.md

@@ -24,11 +24,13 @@ on the standard Config class if nothing is found in the database.
 
 ## User Providers
 
-You can use your own models to handle user persistence. Shield calls this the "User Provider" class. A default model
-is provided for you at `CodeIgniter\Shield\Models\UserModel`. You can change this in the `Config\Auth->userProvider` setting.
-The only requirement is that your new class MUST extend the provided `UserModel`.
+You can use your own models to handle user persistence. Shield calls this the "User Provider" class.
+A default model is provided for you by the `CodeIgniter\Shield\Models\UserModel` class. You can change
+this in the `Config\Auth::$userProvider` setting. The only requirement is that your new class
+MUST extend the provided `UserModel`.
 
-Shield has a CLI command to quickly create a custom `MyUserModel` by running the following command in terminal:
+Shield has a CLI command to quickly create a custom `MyUserModel` class by running the following
+command in the terminal:
 
 ```console
 php spark shield:model MyUserModel