Add default models example for method style

database/relations.md

@@ -332,7 +332,7 @@ public function user(): BelongsTo
 
 #### Default models
 
-The `belongsTo` relationship lets you define a default model that will be returned if the given relationship is `null`. This pattern is often referred to as the [Null Object pattern](https://en.wikipedia.org/wiki/Null_Object_pattern) and can help remove conditional checks in your code. In the following example, the `user` relation will return an empty `Acme\Blog\Models\User` model if no `user` is attached to the post:
+The `belongsTo`, `hasOne`, `hasOneThrough` and `morphOne` relationships allow you to define a default model that will be returned if the given relationship is `null`. This pattern is often referred to as the [Null Object pattern](https://en.wikipedia.org/wiki/Null_Object_pattern) and can help remove conditional checks in your code. In the following example, the `user` relation will return an empty `Acme\Blog\Models\User` model if no `user` is attached to the post:
 
 ```php
 public $belongsTo = [
@@ -351,6 +351,24 @@ public $belongsTo = [
 ];
 ```
 
+If you have defined the relation as a method, you may use the `withDefault()` method to define a default model:
+
+```php
+public function user(): BelongsTo
+{
+    return $this->belongsTo('Acme\Blog\Models\User')->withDefault();
+}
+
+// With attributes
+
+public function user(): BelongsTo
+{
+    return $this->belongsTo('Acme\Blog\Models\User')->withDefault([
+        'name' => 'Guest',
+    ]);
+}
+```
+
 ### One To Many
 
 A one-to-many relationship is used to define relationships where a single model owns any amount of other models. For example, a blog post may have an infinite number of comments. Like all other relationships, one-to-many relationships are defined adding an entry to the `$hasMany` property on your model: