title: How can I load some data into Ext.data.Store
body: <p>this is my code </p>
  
  <pre><code>        var store = {
              roles_store: new Ext.data.Store({
                          autoLoad: false,
                          proxy: new Ext.data.HttpProxy({
                                                          url: 'a/b/c',
                                                        }),
                          remoteSort: true, 
                          baseParams: {
  
                                      },
                          reader: new Ext.data.JsonReader({
                                                  totalProperty: 'total',
                                                  root: 'root',
                                                  fields:['roles']                
                                                          }),
  
              })
          };
  </code></pre>
  
  <p>this is my json</p>
  
  <p>{"total":3,"root":[{"roles":"A"},{"roles":"B"},{"roles":"C"}]}</p>
  
  <p>If I wnat to add data into Ext.data.Store. How can I do?  </p>
  
  <p>(PS:Sorry,my English is not well. And my extjs is :http://docs.sencha.com/ext-js/3-4/#!/api/Ext.data.Store-method-addSorted)</p>