public static void show(Long id) {
    Bowl bowl = Bowl.findById(id);

    List<Participant> bowlParticipants = Participant.calculateShares(bowl);
    List<Bill> bills = Bill.generateByBowl(bowl);

    render(bowl, bowlParticipants, bills);
  }
  public static void expense(Long id) {
    Expense expense = Expense.findById(id);
    List<Bill> bills = Bill.generateByExpense(expense);

    render(expense, bills);
  }