slot_1:
  id: 1
  start_at: 2012-04-11 06:00:00.000000000 Z
  end_at: 2012-04-11 10:00:00.000000000 Z
  created_at: 2012-03-12 13:40:22.342717000 Z
  updated_at: 2012-03-12 13:40:22.342717000 Z
  availability_id: 12
  ex_start_at:
  canceled_at:
  ex_end_at:
  offered:

slot_2:
  id: 2
  start_at: 2015-06-15 12:00:28.000000000 Z
  end_at: 2015-06-15 13:00:28.000000000 Z
  created_at: 2015-06-10 11:20:01.341130000 Z
  updated_at: 2015-06-10 11:20:01.341130000 Z
  availability_id: 13
  ex_start_at:
  canceled_at:
  ex_end_at:
  offered: