title: Sending extra param value via select_tag
body: <p>My View: </p>
  
  <pre><code>&lt;%= form_tag(update_user_products_path, :id =&gt; "update_user_form") do %&gt;
  &lt;%@products.each do |product| %&gt;
              &lt;div class = "prod"&gt;
              &lt;a href='&lt;%= recommendations_path(:product_id =&gt; product.id, :rating_set_id =&gt; params[:rating_set_id]) %&gt;' target="_blank"&gt;&lt;img src='&lt;%= product.cover_img %&gt;' class='product_image_prods'&gt;&lt;/img&gt;&lt;/a&gt;
              &lt;div class= "title"&gt;&lt;small&gt;&lt;b&gt;&lt;%= link_to truncate(product.title, :length =&gt;30),  recommendations_path(:product_id =&gt; product.id, :rating_set_id =&gt; params[:rating_set_id]), :target =&gt; '_blank' %&gt;&lt;/b&gt;&lt;/small&gt;&lt;/div&gt;
              &lt;br/&gt;
              &lt;div&gt;&lt;em&gt;Current Rating: &lt;%= product.rating %&gt; &lt;/em&gt;&lt;/div&gt;
              &lt;%= select_tag "user_id:#{product.id}", options_for_select(User.all.collect {|u| [ u.name, u.id ] })%&gt;
              &lt;/div&gt;
              &lt;% end %&gt;
      &lt;%= submit_tag %&gt;
  &lt;% end %&gt;
  </code></pre>
  
  <p>I need to send 2 params to my controller update action -- product.id of each record and user.id for the selected record. Calling params.keys returns:</p>
  
  <pre><code>utf8
  authenticity_token
  user_id:1
  user_id:2
  user_id:3
  user_id:4
  ...
  user_id:78
  commit
  action
  controller
  </code></pre>
  
  <p>I an able to split params.keys by (":"). Doing this returns the same output as params.keys. Is there another way to pass product.id to my update_user action?</p>