title: ExtJs - Unable to save a store to localStorage
body: <p>I have a store with a localstorage proxy, but I'm unable to save the data.
  The code is quite simple:</p>
  
  <pre><code>onToolbarTicketsadd: function(me){
      var tickets = this.getStore('Tickets');
      tickets.add({id: 1, name: 'new'})
      console.log(tickets.getById(1), tickets.count())
      tickets.sync({callback: function(){console.log('synched')}})
  },
  </code></pre>
  
  <p>The ticket gets added to the store, as the first <code>console.log</code> proves, but the <code>sync()</code> command does not work. The localStorage inspector only shows an empty entry <code>Tickets: ''</code>, and the <code>callback</code> function also does not get called.</p>
  
  <p><strong>What am I missing ? What is necessary for a localstorage proxy to work ?</strong></p>
  
  <p>Note: The problem is not with the browser: I'm on the latest Chrome and Firefox.</p>
  
  <p>Here is the code for the store and the model:</p>
  
  <pre><code>Ext.define('App.store.Tickets', {
      extend: 'Ext.data.Store',
      model: 'App.model.Ticket',
      proxy: {
          type: 'localstorage',
          id: 'Tickets'
      }
  });
  
  Ext.define('App.model.Ticket', {
      extend: 'Ext.data.Model',
      fields: [
          {name: 'id', type: 'int'},
          {name: 'name', type: 'string'}
      ]
  });
  </code></pre>
  
  <p>A demo of the problem is <a href="http://romanel.bible.ch/ext-test/sandbox/" rel="nofollow">here</a>.</p>