title: cannot read property 'fromJS' of undefined in external viewmodel.js
body: <p>I keep getting the error : <strong>Uncaught TypeError: Cannot read property 'fromJS' of undefined</strong>
  The idea is to have 2 pages, where is the the ui representation and the other one is het viewmodel.
  I have 2 pages:</p>
  
  <p>Index.html</p>
  
  <pre><code>&lt;link rel="stylesheet" href="bin/styles/kendo.common.min.css" /&gt;
  &lt;link rel="stylesheet" href="bin/styles/kendo.default.min.css" /&gt;
  &lt;link rel="stylesheet" href="bin/styles/kendo.dataviz.min.css" /&gt;
  &lt;link rel="stylesheet" href="bin/styles/kendo.dataviz.default.min.css" /&gt;
  
  &lt;script src="bin/js/jquery.min.js"&gt;&lt;/script&gt;
  &lt;script src="bin/js/kendo.all.min.js"&gt;&lt;/script&gt;
  &lt;script src="bin/knockout-3.2.0.js"&gt;&lt;/script&gt;
  &lt;script src="bin/knockout.mapping-latest.js" type="text/html"&gt;&lt;/script&gt;
  
  &lt;script src="IndexViewModel.js"&gt;&lt;/script&gt;
  
  &lt;script&gt;
      $(function() {
          var indexVM = new IndexViewModel.ViewModel();
          ko.applyBindings(indexVM);
      });
  &lt;/script&gt;
  
  
  &lt;table&gt;
      &lt;thead&gt;&lt;tr&gt;
          &lt;th&gt;First Name&lt;/th&gt;
      &lt;/tr&gt;&lt;/thead&gt;
      &lt;tbody data-bind="foreach: Users"&gt;
          &lt;tr&gt;
              &lt;td data-bind="text: UserName"/&gt;&lt;/td&gt;
          &lt;/tr&gt;
      &lt;/tbody&gt;
  &lt;/table&gt;
  </code></pre>
  
  <p>and IndexViewModel.js :</p>
  
  <pre><code>var IndexViewModel = (function (IndexViewModel) {
  IndexViewModel.ViewModel = function() {
      var self = this;
      self.Users = ko.observableArray();
      $.ajax({
          url : 'GetUsers.php',
          dataType: 'json',
          success: function(data){ //json string of the student records returned from the server
          self.Users = ko.mapping.fromJS(result.data, {}, self.Users);
          }
      });
  }
      return IndexViewModel;
  }(IndexViewModel || {}));
  </code></pre>
  
  <p>What am I doing wrong / missing?</p>
  
  <p>Thanks</p>