title: simple Flickr application with Knockout.js doesn't work (JSBin prepared)
body: <p>Now I'm writing a simple application which get five photos from Flickr and display the titles as list. At first I tried <code>@current_photos</code> and this works good, but when I use Knockout.js(<code>@currentPhotos</code>), this doesn't work.</p>
  
  <pre><code>root = exports ? this
  class root.Flickr
    constructor: -&gt;
      @photos = []
      $.getJSON(
        'http://www.flickr.com/services/rest/?jsoncallback=?'
          format : 'json'
          method : 'flickr.photos.search'
          api_key : '7965a8bc5a2a88908e8321f3f56c80ea'
          user_id : '29242822@N00'
          per_page : 5
      ).done((data) =&gt;
        $.each data.photos.photo, (i, item) =&gt;
          @photos.push item
      )
  
  root = exports ? this
  class root.PhotoListViewModel
    index = null
    currentPhotos = []
    constructor: -&gt;
      flickr = new Flickr
      # @current_photos = flickr.photos ###### WORKS GOOD
      flickr.photos = ko.observableArray []
      @currentPhotos = ko.computed -&gt;
        flickr.photos
  </code></pre>
  
  <p>HTML is as below:</p>
  
  <pre><code>&lt;body&gt;
  
  &lt;h4&gt;Photo List&lt;/h4&gt;
  &lt;ul data-bind="foreach: currentPhotos"&gt;
      &lt;li&gt;
        title: &lt;span data-bind="text: title"&gt; &lt;/span&gt;
      &lt;/li&gt;
  &lt;/ul&gt;
  
  &lt;/body&gt;
  </code></pre>
  
  <p>I created JSBin page as below:
  <a href="http://jsbin.com/avazak/7/" rel="nofollow">http://jsbin.com/avazak/7/</a></p>
  
  <p>Thanks for your kindness.</p>