one more out-of-date-doc tweak

index.html

@@ -1275,7 +1275,7 @@ <h2 id="Sync">Backbone.sync</h2>
 def update
   account = Account.find(params[:id])
   account.update_attributes JSON.parse params[:model]
-  render :json => {:model => account}
+  render :json => account
 end
 </pre>