code: function addEvent (date, value) {
    date = this.toDate(date);
    if (!date) {
      return null;
    }
    var info = getDayInfo(this.dayInfo, date, true);
    if (!info) {
      return null;
    }
    var events = info.events;
    events.push(value);
    return events.length - 1;
  }
docs: イベントを設定
  @method addEvent
  @param  {DATE} date
  @param  {Array}       value
  @return {Number}      index