How to add products to a company?

In my company form, I would like to be able to add products directly. Basically, a company can have many products.

class Company < ActiveRecord::Base
  has_many :company_products
  has_many :products, :through => :company_products

  accepts_nested_attributes_for :products, :reject_if => lambda { |a| a[:name].blank? }, :allow_destroy => true
end

My Form:

<%= form_for(@company) do |f| %>

  <ul>

    <li class="clearfix">
      <%= f.label :company_name %>
      <%= f.text_field :company_name %>
    </li>

    <li>
      <%= f.collection_select :product_ids, Product.all, :id, :name, { :prompt => 'Select a product' } %>
    </li>

    <li>
      <%= f.collection_select :product_ids, Product.all, :id, :name, { :prompt => 'Select a product' } %>
    </li>

    <li>
      <%= f.collection_select :product_ids, Product.all, :id, :name, { :prompt => 'Select a product' } %>
    </li>
 ....

Above, does not exactly work. Since it only adds the product that was selected in the last f.collection开发者_StackOverflow_select.

This is what I am trying to achieve. In console, I do:

company.update_attributes({"product_ids"=>["1", "2", "3"]})

Which would assign products with id: 1, 2 and 3 to the specified company.

What is the proper way to do this in Rails 3?

EDIT

In my form, it works with:

<%= f.collection_select :product_ids, Product.all, :id, :name, { :prompt => 'Select a product'},{ :multiple => true } %>

Is there a way to do this with select dropdown boxes instead?

Use nested forms for products:

<%= fields_for @company.products do |product_fields| %> <%= product_fields.collection_select :product_id, Product.all, :id, :name, { :prompt => 'Select a product' } %> <% end %>