code: function isListCompleted() {
  		var todos = todosDB.getList();
  		var len = todos.length;
  		var isComplete = len > 0;
  		for (var i = 0; i < len; i++) {
  			if (!todos[i].completed) {
  				isComplete = false;
  				break;
  			}
  		}
  		return isComplete;
  	}
docs: Returns true if all todos in the list are complete
  @returns {boolean}
  @private