Ruby on rails Rails：通过关联使用has\u many:显示对象名称

我有三个模型（如下所列）：用户、线程和一个称为发布的连接

我正在成功列出用户的所有出版物，并显示出版物的用户id和线程id

我不想列出发布的信息，而是想使用每个发布的线程id显示每个发布的线程名称

以下是我的用户模型：

class User < ActiveRecord::Base

    devise :database_authenticatable, :registerable, :confirmable,
           :recoverable, :rememberable, :trackable, :validatable

    attr_accessible :email, :password, :password_confirmation, 
                    :remember_me, :username, :profile_image, 
                    :first_name, :last_name

    has_many :publications
    has_many :threads, :through => :publications

end

下面是我的索引视图中的代码，其中列出了用户的所有出版物：

%table
  %tr
    %th Publication
    %th User
    %th Created at

  - @publication.each do |publication|
    %tr
      %td= publication.thread_id
      %td= publication.user_id
      %td= publication.created_at

---

请使用关联关系表

%table
  %tr
    %th Publication
    %th User
    %th Created at

  - @publication.each do |publication|
    %tr
      %td= publication.thread.name
      %td= publication.user.username
      %td= publication.created_at

def index
  @user = current_user
  @threads = @user.threads.all
  @publications = @user.publications.all
end

%table
  %tr
    %th Publication
    %th User
    %th Created at

  - @publication.each do |publication|
    %tr
      %td= publication.thread_id
      %td= publication.user_id
      %td= publication.created_at

%table
  %tr
    %th Publication
    %th User
    %th Created at

  - @publication.each do |publication|
    %tr
      %td= publication.thread.name
      %td= publication.user.username
      %td= publication.created_at