title: Properties not changing on the DOM after a GET request
body: <p>I am working on a component to render user details. The details are fetched from an API request and properties are updated but these changes are not reflected on the DOM.</p>
  
  <p>The company I work for is still using Polymer 1.2 and I am having difficulty finding and understanding the documentation. Do I need to make the get request from the parent component or is it possible to do this directly inside the component? There is something fundamental I am not grasping about this and wondering if someone could shed some light on it for me.</p>
  
  <p>Thank you.</p>
  
  <p>Snippet from the template:</p>
  
  <pre><code>&lt;p&gt;{{i18n.GLOBAL_USERNAME}} - [[username]]&lt;/p&gt;
  &lt;p&gt;{{i18n.GLOBAL_FIRSTNAME}} - [[firstname]]&lt;/p&gt;
  &lt;p&gt;{{i18n.GLOBAL_LASTNAME}} - [[lastname]]&lt;/p&gt;
  &lt;p&gt;{{i18n.GLOBAL_EMAIL}} - [[email]]&lt;/p&gt;
  &lt;p&gt;{{i18n.GLOBAL_NUMBER}} - [[number]]&lt;/p&gt;
  
  </code></pre>
  
  <p>Snippet from the polymer functions:</p>
  
  <pre><code>Polymer({
              is: 'my-component',
  
              properties: {
                  username: { 
                      type: String, 
                      value: "n/a",
                  },
                  firstname: { 
                      type: String, 
                      value: "n/a"
                  },
                  lastname: { 
                      type: String, 
                      value: "n/a"
                  },
                  email: { 
                      type: String, 
                      value: "n/a"
                  },
                  number: { 
                      type: String, 
                      value: "n/a"
                  },
              },
  
              ready: function () {
                  var user = app.auth.hasSession()
                  if (user !== null) {
                      app.getUserInfo(user.user_id, this._getUserSuccessful, this._getUserFail);
                  }
              },
  
              _getUserSuccessful: function (res) {
                  this.username = res.user.user_id
                  this.firstname = res.user.firstname
                  this.lastname = res.user.lastname
                  this.email = res.user.email
                  this.number = res.user.phone_number
                  console.log("got user details")
              },
              _getUserFail: function () {
                  console.log("failed to get user details")
              },
          });
  </code></pre>