title: has_and_belongs_to_many assocation is not working
body: <p>I have a problem with a <code>has_and_belongs_to_many</code> association in my Ruby On Rails project.</p>
  
  <p>Here are my models:</p>
  
  <pre><code>class Store &lt; ActiveRecord::Base
    attr_accessible :address, :city, :map_url, :name, :uimage_url
    has_and_belongs_to_many  :furnitures_id
  end
  
  class Furniture &lt; ActiveRecord::Base
    attr_accessible :description, :image_url, :maintenance, :name, :size
    has_and_belongs_to_many  :store_id
  end
  </code></pre>
  
  <p>This is my join table migration:</p>
  
  <pre><code>create_table "furnitures_stores", :id =&gt; false, :force =&gt; true do |t|
    t.integer "furniture_id"
    t.integer "store_id"
  end
  </code></pre>
  
  <p>I then tried to insert some values with seed.rb:</p>
  
  <pre><code>Furniture.delete_all
  furnitures =  Furniture.create([{name: 'aaaa 1'}])
  
  Store.delete_all
  storee =  Store.create([{name: 'S 1'}])
  </code></pre>
  
  <p>But it doesn't work; I have this error: </p>
  
  <pre><code>**rake aborted!
  uninitialized constant Store::FurnituresId**
  </code></pre>