title: gojs with vuejs and webpack
body: <p>I'm trying to set up a simple gojs diagram into vuejs + webpack. 
  I installed gojs with npm and imported it on my project in the main.js file: <code>import go from 'gojs'</code>
  Now my problem is how to make things work in the component implementation, that's the code of the component Diagram.vue: </p>
  
  <pre><code>&lt;template&gt;
     &lt;div id="myDiagramDiv" style="width:300px; height:300px;"&gt;&lt;/div&gt;
  &lt;/template&gt;
  
  &lt;script&gt;
     export default {
        name: 'Diagram', 
        data: function () {
           return {
              nodeDataArray: [
                 {key:1, text:"Alpha"},
                 {key:2, text:"Beta"}
              ],
              linkDataArray: [
                 {from:1, to:2}
              ]
           }
        },
        methods: {
           getUnits: function(){
              var $ = go.GraphObject.make;
              myDiagram = $(go.Diagram, "myDiagramDiv");
              myDiagram.model = new go.GraphLinksModel(nodeDataArray, linkDataArray);
           }
        },
        mounted: function(){
           this.getUnits();
        }
  }
  &lt;/script&gt;
  </code></pre>
  
  <p>it compiles without error but I can only see a white empty box...</p>