title: set attribute of all models in backbone collection
body: <p>I understand that using pluck method we can get an array of attributes of each model inside a backbone collection</p>
  
  <pre><code>var idsInCollection = collection.pluck('id'); // outputs ["id1","id2"...]
  </code></pre>
  
  <p>I want to if there is a method that sets up an attribute to each model in the collection, </p>
  
  <pre><code>var urlArray = ["https://url1", "https://url1" ...];
  collection.WHAT_IS_THIS_METHOD({"urls": urlArray});
  </code></pre>