Rails嵌套表单仅向预订添加一个Passenger对象

<%= form_for @booking do |f| %>
  <%= f.label :booking_number %>
  <%= f.text_field :booking_number %>

  <%= f.fields_for :passenger do |passenger_fields| %>
    <%= passenger_fields.label :name %>
    <%= passenger_fields.text_field :name %>

    <%= passenger_fields.label :age %>
    <%= passenger_fields.number_field :age %>
  <% end %>

  <%= f.submit "Create Booking" %>
<% end %>

class BookingsController < ApplicationController
  def new
    @booking = Booking.new
    @booking.build_passenger
  end

  def create
    @booking = Booking.new(booking_params)

    if @booking.save
      redirect_to @booking
    else
      render 'new'
    end
  end

  private

  def booking_params
    params.require(:booking).permit(:booking_number, passenger_attributes: [:name, :age])
  end
end

class Booking < ApplicationRecord
  has_one :passenger
  accepts_nested_attributes_for :passenger
end