title: How to config custom URL of Laravel-stapler
body: <p>I use Laravel4 with Laravel-stapler to manipulate images.</p>
  
  <p>I am designing the product catalog on web, there are two table. </p>
  
  <ol>
  <li>Table "Product" has the information about product, such as, product name, product size, product description and <strong>a product highlight image</strong>.</li>
  <li>Table "Product_Gallery" has the unlimit images of product.</li>
  </ol>
  
  <p>And, I set the model as below,</p>
  
  <pre><code>class Products extends Eloquent implements StaplerableInterface {
       public function __construct(array $attributes = array()) {
          $this-&gt;hasAttachedFile('product_main_image', [
                  'styles' =&gt; [
                          'thumb' =&gt; ['dimensions' =&gt; '100x100#' ],                       
                          'display' =&gt; ['dimensions' =&gt; '300x300#' ],
  
                  ],
                  'url' =&gt; '/uploads/product/:id/:style/:filename',                   
          ]);
  ...
  
  
  class ProductGallery extends Eloquent implements StaplerableInterface {
       public function __construct(array $attributes = array()) {
          $this-&gt;hasAttachedFile('product_gallery', [
                  'styles' =&gt; [
                          'thumb' =&gt; ['dimensions' =&gt; '100x100#' ],                       
                          'gallery' =&gt; ['dimensions' =&gt; '1024x' ],
  
                  ],
                  'url' =&gt; '/uploads/gallery/:id/:style/:filename',                   
          ]);
  ...
  </code></pre>
  
  <p>When I upload a product and  with four gallery files, they storage as below,</p>
  
  <pre><code>/uploads/product/1/thumb/aaaa.jpg
  /uploads/gallery/1/thumb/g1.jpg
  /uploads/gallery/2/thumb/g2.jpg
  /uploads/gallery/3/thumb/g3.jpg
  /uploads/gallery/4/thumb/g4.jpg
  </code></pre>
  
  <p>I would like to group the file upload of product gallery into product folder, for example,</p>
  
  <pre><code>/uploads/product/1/thumb/aaaa.jpg
  /uploads/product/1/gallery/1/thumb/g1.jpg
  /uploads/product/1/gallery/2/thumb/g2.jpg
  /uploads/product/1/gallery/3/thumb/g3.jpg
  /uploads/product/1/gallery/4/thumb/g4.jpg
  </code></pre>
  
  <p>This code in Controller,</p>
  
  <pre><code>    $model = new ProductGallery();
      $model-&gt;fk_id = $product_id;
      $model-&gt;image = Input::file('file');
      $pathInfo = pathinfo(Input::file('file')-&gt;getClientOriginalName());
      $newFilename =  'gallery-' . date("Ymd-") . sha1(time()) . '.' . $pathInfo['extension'];
      $model-&gt;image-&gt;instanceWrite('file_name', $newFilename);        
      $model-&gt;save();
  </code></pre>
  
  <p><strong><em>How to config the Laravel-stapler?</em></strong></p>