handleSubmit = (e) => {
     e.preventDefault();
     this.props.addTodo(this.state.item);
     this.setState({item: ''}, function() {
       this.refs.item.focus();
     });
   }

  handleSubmit = (e) => {
    e.preventDefault();
    this.props.addTodo(this.state.item);
    this.setState(
        {item: ''}, 
        this.focus_input() 
    );
  }

  focus_input = () => {
      this.refs.item.focus();
  }