如何在使用nested_form (has_many belongs_to关联)更新对象时创建另一个对象

gem 'nested_form'

class Post < ApplicationRecord
  has_many :comments
  accepts_nested_attributes_for :comments, allow_destroy: true
end

class Comment < ApplicationRecord
  belongs_to :post
end

<%= nested_form_for @post do |f| %>
  <%= f.label :title %>
  <%= f.text_field :title %>

  <%= f.fields_for :comments do |comment_form| %>
    <%= comment_form.label :content %>
    <%= comment_form.text_area :content %>
    <%= comment_form.link_to_remove "删除评论" %>
  <% end %>

  <%= f.link_to_add "添加评论", :comments %>

  <%= f.submit "保存" %>
<% end %>

def update
  @post = Post.find(params[:id])
  if @post.update(post_params)
    # 更新成功的逻辑
  else
    # 更新失败的逻辑
  end
end

private

def post_params
  params.require(:post).permit(:title, comments_attributes: [:id, :content, :_destroy])
end