move(newCardId) {
    // update every activity
    ReactiveCache.getActivities(
      {checklistId: this._id}
    ).forEach(activity => {
      Activities.update(activity._id, {
        $set: {
          cardId: newCardId,
        },
      });
    });
    // update every checklist-item
    ReactiveCache.getChecklistItems(
      {checklistId: this._id}
    ).forEach(checklistItem => {
      ChecklistItems.update(checklistItem._id, {
        $set: {
          cardId: newCardId,
        },
      });
    });
    // update the checklist itself
    return {
      $set: {
        cardId: newCardId,
      },
    };
  }
move the checklist to another card
@param newCardId move the checklist to this cardId