Fixed update and insert methods when calling on relationships.

Fixes #360

Author: mikebronner

src/Traits/Buildable.php

@@ -114,8 +114,10 @@ public function inRandomOrder($seed = '')
 
     public function insert(array $values)
     {
-        $this->checkCooldownAndFlushAfterPersisting($this->model);
-
+        if (property_exists($this, "model")) {
+            $this->checkCooldownAndFlushAfterPersisting($this->model);
+        }
+        
         return parent::insert($values);
     }
 
@@ -202,7 +204,9 @@ public function sum($column)
 
     public function update(array $values)
     {
-        $this->checkCooldownAndFlushAfterPersisting($this->model);
+        if (property_exists($this, "model")) {
+            $this->checkCooldownAndFlushAfterPersisting($this->model);
+        }
 
         return parent::update($values);
     }

tests/Integration/CachedBuilder/UpdateRelationTest.php

@@ -0,0 +1,26 @@
+<?php namespace GeneaLabs\LaravelModelCaching\Tests\Integration\CachedBuilder;
+
+use GeneaLabs\LaravelModelCaching\Tests\Fixtures\Book;
+use GeneaLabs\LaravelModelCaching\Tests\IntegrationTestCase;
+
+class UpdateRelationTest extends IntegrationTestCase
+{
+    public function testInRandomOrderCachesResults()
+    {
+        $book = (new Book)
+            ->with("stores")
+            ->whereHas("stores")
+            ->first();
+        $book->stores()
+            ->update(["name" => "test store name change"]);
+        $updatedCount = (new Book)
+            ->with("stores")
+            ->whereHas("stores")
+            ->first()
+            ->stores()
+            ->where("name", "test store name change")
+            ->count();
+
+        $this->assertEquals(1, $updatedCount);
+    }
+}