title: extjs treestore with proxy
body: <p>I'm creating a MVC extjs application. I've got a treepanel with a store, which is loading the data from a php source.
  I get the following json-formatted response:</p>
  
  <pre><code>[
  {
      "text": "Home",
      "leaf": true,
      "dbName": "NULL",
      "children": []
  },
  {
      "text": "Moje Firma s.r.o.",
      "leaf": false,
      "expanded": false,
      "children": [
          {
              "text": "Vydane",
              "leaf": true,
              "dbName": "demo"
          },
          {
              "text": "Prijate",
              "leaf": true,
              "dbName": "demo"
          }
      ]
  },
  {
      "text": "Já Živnostník",
      "leaf": false,
      "expanded": false,
      "children": [
          {
              "text": "Vydane",
              "leaf": true,
              "dbName": "demo_de"
          },
          {
              "text": "Prijate",
              "leaf": true,
              "dbName": "demo_de"
          }
      ]
  },
  {
      "text": "Nezisková organizace",
      "leaf": false,
      "expanded": false,
      "children": [
          {
              "text": "Vydane",
              "leaf": true,
              "dbName": "demo_neziskova"
          },
          {
              "text": "Prijate",
              "leaf": true,
              "dbName": "demo_neziskova"
          }
      ]
  },
  {
      "text": "Příspěvková organizace",
      "leaf": false,
      "expanded": false,
      "children": [
          {
              "text": "Vydane",
              "leaf": true,
              "dbName": "demo_prispevkovka"
          },
          {
              "text": "Prijate",
              "leaf": true,
              "dbName": "demo_prispevkovka"
          }
      ]
  },
  {
      "text": "Moje Firma SK s.r.o.",
      "leaf": false,
      "expanded": false,
      "children": [
          {
              "text": "Vydane",
              "leaf": true,
              "dbName": "demo_sk"
          },
          {
              "text": "Prijate",
              "leaf": true,
              "dbName": "demo_sk"
          }
      ]
  }
  ]
  </code></pre>
  
  <p>My store: </p>
  
  <pre><code>Ext.define('Statistics.store.Menu', {
  extend: 'Ext.data.TreeStore',
  model: 'Menu',
  autoLoad: true,
  autoSync: true,
  
  proxy   : {
      type : 'ajax',
      url  : 'data.json',
      reader: {
          type: 'json'
      }
  }
  
  
  });
  </code></pre>
  
  <p>And model:</p>
  
  <pre><code>Ext.define('Statistics.model.Menu', {
  extend: 'Ext.data.Model',
  
  fields: [
      {name: 'text', type: 'string'},
      {name: 'leaf', type: 'boolean'},
      {name: 'expanded', type: 'boolean', defaultValue: false},
      {name: 'dbName', type: 'string', defaultValue: 'NULL'}
  ],
  
  });
  </code></pre>
  
  <p>This configuration works, when the data are saved in a .json file. But id doesn't work, when they are loaded from a php source.</p>
  
  <p>Thanks for any answer.</p>