title: Automatic update with new data on ext.data.store
body: <p>I have this extjs data store</p>
  
  <pre><code>    mystore= Ext.create('Ext.data.Store', {
          id: 'store_id',
          fields: ['label', 'value', 'id', 'type'],
          autoLoad: true,
          proxy: {
              type: 'ajax',
              url: 'url/to/controller',
              reader: {
                  type: 'json',
                  root: 'MyModel'
              }
          }
      });
  </code></pre>
  
  <p>Is it possible with extjs configuration to make this store send ajax requests for new data on some interval (example 5 secs) automatically?  </p>
  
  <p>I want to use all functionality that extjs can provide so that I don't use php or additional javascript. </p>