Add pivot class property (#1518)

* Add pivot class property

* Add test for pivot class properties

* Fix failed test for pivot class properties

* Update CHANGELOG.md

* Fix failed test

tests/Console/ModelsCommand/Pivot/Models/ModelWithPivot.php

@@ -0,0 +1,16 @@
+<?php
+
+namespace Barryvdh\LaravelIdeHelper\Tests\Console\ModelsCommand\Pivot\Models;
+
+use Barryvdh\LaravelIdeHelper\Tests\Console\ModelsCommand\Pivot\Models\Pivots\CustomPivot;
+use Illuminate\Database\Eloquent\Model;
+
+class ModelWithPivot extends Model
+{
+    public function relationWithCustomPivot()
+    {
+        return $this->belongsToMany(ModelwithPivot::class)
+            ->using(CustomPivot::class)
+            ->as('customAccessor');
+    }
+}