DateTime calendar = start;
calendar = calendar.plusDays(i).withHourOfDay(
6 + random.nextInt(10));
Event event = new Event();
int id = (int) (j * duration.days() + i);
event.setId("" + id);
event.setTitle(title + (1 + i));
event.setStart(calendar);
calendar = calendar.plusHours(random.nextInt(8));
event.setEnd(calendar);