findAppropriateSlotsToShift(tasksToShift, freeSlots) {
    let sortedTasksByPriority = _.reverse(tasksToShift);
    let sortedFreeSlotsByPriority = _.reverse(freeSlots);
    let hoursToFree = this.estimation - this.totalAvailHours;
    let counter = 0;

    _.forEach(sortedTasksByPriority, (value, key) => {
      let slotDuration = value.slots.futureSlots[counter].duration;
      let freePlaces = sortedFreeSlotsByPriority[counter];

      if (hoursToFree <= 0) { return false; }

      _.forEach(Object.keys(freePlaces), (freeDay, index) => {

        if (hoursToFree <= 0) { return false; }

        _.forEach(freePlaces[freeDay], (freeSlot, i) => {
          if (freeSlot.duration >= slotDuration) {

            value.slots.futureSlots[counter].start = freeSlot.start;
            value.slots.futureSlots[counter].end = new Date(new Date(freeSlot.start).setHours(new Date(freeSlot.start).getHours() + value.slots.futureSlots[counter].duration)).toISOString();

            hoursToFree -= slotDuration;

            freeSlot.start = value.slots.futureSlots[counter].end;
            freeSlot.duration = freeSlot.duration - value.slots.futureSlots[counter].duration;

            sortedFreeSlotsByPriority = this._freeSlotsUpdate(freeDay, freePlaces[freeDay], sortedFreeSlotsByPriority);

            console.log(this.Slots);

            this.Slots.update(value.slots.futureSlots[counter]);
            return false;
          }
        });
      });

      counter = (key === sortedTasksByPriority.length) ? counter + 1 : counter;
    });
  }