title: Laravel Crinsane/LaravelShoppingcart associate() doesn't work
body: <p>In my <strong>Laravel</strong> I'm using <a href="https://github.com/Crinsane/LaravelShoppingcart" rel="nofollow noreferrer">this shoppingcart </a> . </p>
  
  <p>When I add one product to my shopping cart I want to have <code>associate()</code> with <code>App\Product</code> Model . </p>
  
  <p>This is my code : </p>
  
  <pre><code>public function store(Request $request)
  {
      // store product information to Cart
      Cart::add($request-&gt;id, $request-&gt;name, 1, $request-&gt;price)
        -&gt;associate('App\Product');
  
      return redirect(route('cart.index'))
        -&gt;with('success_message', 'محصول با موفقیت به سبد اضافه شد');
  }
  </code></pre>
  
  <p>But when I want to access model <code>$item-&gt;model-&gt;id</code> in view I get this error : </p>
  
  <pre><code>Trying to get property 'id' of non-object (View: C:\xampp\htdocs\digikala\resources\views\cart.blade.php)
  </code></pre>
  
  <p>Edit : </p>
  
  <p>my cart view (<code>cart.blade.php</code>) codes : </p>
  
  <pre><code>  &lt;table border="1" class="table"&gt;
        @foreach (Cart::content() as $item)
          {{ $item-&gt;model-&gt;id }}
        @endforeach
      &lt;/table&gt;
  </code></pre>