Orbit/app/views/admin/user_attributes/_form.html.erb

<p>
       <%= f.label :name %>
       <%= f.text_field :name %>
</p>

<fieldset>
   <% @user_attribute.attrs.each_with_index do |attr, i| %>
   <p>
       <label><%= attr["key"] %></label>
       <%= hidden_field_tag "user_attribute[attrs][][key]", attr["key"] %>
       <%= text_field_tag "user_attribute[attrs][][name]", attr["name"] %>
       <%= select_tag "user_attribute[attrs][][type]", options_for_select(["text_field", "select"], attr["type"]) %>
       <a href="#" class="remove">(remove)</a>
   </p>
   <% end -%>
   
   <p id="newone">
       <label>Key</label>
       <%= text_field_tag "user_attribute[attrs][][key]", "" %>
       <label>Name</label>
       <%= text_field_tag "user_attribute[attrs][][name]", "" %>
       <%= select_tag "user_attribute[attrs][][type]", options_for_select(["text_field"], "") %>
       <a href="#" class="remove">(remove)</a>
   </p>
   
   <a href="#" class="add">(add)</a>
      
</fieldset>

<% content_for :page_specific_javascript do %>
    <script type="text/javascript" charset="utf-8">
        var newone = $('fieldset #newone').clone();
        $('fieldset #newone').remove();
        
        $('fieldset a.remove').live( "click", function(){
            $(this).parent().remove();
        });
        
        $('fieldset a.add').click(function(){
            newone.clone().appendTo( $('fieldset') );
        })
    </script>
<% end -%>