title: Magento 2 How to get category by url_key
body: <p>I try to get a category in Magento 2.0 by it url_key. </p>
  
  <p>Now I've got :</p>
  
  <pre><code>        $objectManager = \Magento\Framework\App\ObjectManager::getInstance();
          $categoryFactory = $objectManager-&gt;create('Magento\Catalog\Model\CategoryFactory');
          $category = $categoryFactory-&gt;create()
              -&gt;addAttributeToFilter('url_key','my_category_url_key');
  </code></pre>
  
  <p>It returns me this error :</p>
  
  <blockquote>
    <p>Error filtering template: Invalid method
    Magento\Catalog\Model\Category\Interceptor::addAttributeToFilter(Array
    ( [0] => url_key [1] => my_category_url_key ) )</p>
  </blockquote>
  
  <p>Thanks.</p>