title: How to populate polymer-dropdown-menu on click of a button?
body: <p>I have a <code>polymer-dropdown-menu</code> element in my HTML page which is like this:</p>
  
  <pre><code>   &lt;script src="http://www.polymer-project.org/platform.js"&gt;&lt;/script&gt;
  &lt;link rel="import" href="http://www.polymer-project.org/components/polymer/polymer.html"&gt;
  &lt;link rel="import" href="http://www.polymer-project.org/components/paper-button/paper-button.html"&gt;
  &lt;link rel="import" href="http://www.polymer-project.org/components/paper-dropdown-menu/paper-dropdown-menu.html"&gt;
      &lt;link rel="import" href="http://www.polymer-project.org/components/paper-dropdown/paper-dropdown.html"&gt;
   &lt;link rel="import" href="http://www.polymer-project.org/components/core-menu/core-menu.html"&gt;  
   &lt;polymer-element name="sample"&gt;
       &lt;template&gt;
           &lt;div&gt;
  &lt;paper-dropdown-menu id="Combo" label="Process"&gt;
      &lt;paper-dropdown class="dropdown"&gt;
          &lt;core-menu class="menu"&gt;
              &lt;template repeat="{{processlist}}"&gt;
                  &lt;paper-item&gt;{{}}&lt;/paper-item&gt;
              &lt;/template&gt;
          &lt;/core-menu&gt;
      &lt;/paper-dropdown&gt;
  &lt;/paper-dropdown-menu&gt;
           &lt;/div&gt;
           &lt;div&gt;
               &lt;paper-button id="start_button" raised&gt;Start&lt;/paper-button&gt;   
           &lt;/div&gt;         
           &lt;/template&gt;
  
    &lt;script&gt;
    Polymer({
      created: function() {    
      },
      domReady: function() {
        this.processlist = ["hi","hello"];                   
        var self = this;
        this.$.start_button.addEventListener('click', function () {  
         this.processlist=["hey","how","are","you"];        
        });
        });
      }
    }); 
    &lt;/script&gt;
       &lt;/polymer-element&gt;
  </code></pre>
  
  <p>I need to populate the processlist on click of a button. I write code in my button's event listener function  which updates the process list but this isn't working. </p>
  
  <p>I am able to show a static array of values but not dynamically on click of a button.</p>
  
  <p>Any help would be appreciated. I am fairly new to HTML, JavaScript, and of course polymer.</p>