todos_controller.js

App.TodosController = Ember.ArrayController.extend({
  actions: {
    createTodo: function () {
      // Get the todo title set by the "New Todo" text field
      var title = this.get('newTitle');
      if (!title.trim()) { return; }

      // Create the new Todo model
      var todo = this.store.createRecord( App.Todo, {
        title: title,
        isCompleted: false
      });

      // Clear the "New Todo" text field
      this.set('newTitle', '');

      // Save the new model
      todo.save();
    },

    clearCompleted: function () {
      var completed = this.filterBy('isCompleted', true);
      completed.invoke('deleteRecord');
      completed.invoke('save');
    }
  },