Making a new join in a habtm relationship

Rails
1

I have a class (Article) that has a habtm relationship with ‘links’,
where links are also Articles. I’ve got a join table called
articles_links, and have set up the relationship so that it understands
what’s going on (i think):

  1. class Article < ActiveRecord::Base
  2. has_and_belongs_to_many :links,
  3. :class_name => "Article",

  4. :association_foreign_key => "link_id",

  5. :join_table => "articles_links"

When i make a new link, using a form, the article is created fine but i
can’t work out how to create the join. I’m sure this is simple but i
can’t find out how. My ‘create link’ method looks like this:

  1. def create_link
  2. @link = Article.new(params[:article])

  3. #set some attributes of the new object

  4. if @link.title == ""

  5.   @link.title =

(Hpricot(open(@link.url))/“title”).first.inner_html
6. end
7. @link.added_at = DateTime.now.to_s
8. @link.user_id = session[:user].id
9. @link.points = 0
10. #then save it and return to the original article page
11. if @link.save
12. flash[:notice] = ‘Link was successfully created.’
13. redirect_to :action => ‘show’, :id => params[:article].id
14. else
15. flash[:warning] = ‘Could not create link’
16. render :action => ‘new_link’
17. end
18. end

Can anyone explain to me how to set up the join properly?