app/views/active_extend/_one_to_many_inputs_fields.html.erb
<fieldset>
<% inputs.each do |input,options| %>
<%= f.input input, options %>
<% end %>
<%= f.hidden_field :_destroy %>
<%= link_to '#', class: "remove_fields btn btn-small" do %>
<i class="icon-remove"></i>
<% end %></span>
</fieldset>