Convert delivery methods from radio buttons to select options

1 - NEW _delivery.html.erb

<%= form.select :shipping_method, shipping_methods_for_select(@order) %>

1 - NEW checkout_helper.rb

def shipping_methods_for_select(order)
  order.rate_hash.each do |shipping_method|
    content_tag(:option, "#{shipping_method[:name]} #{shipping_method[:cost]}", :value => shipping_method[:id])
  end.join.html_safe
end

3 - OLD _delivery.html.erb

<% @order.rate_hash.each do |shipping_method| %>
  <label>
    <%= radio_button(:order, :shipping_method_id, shipping_method[:id]) %>
    <% if Spree::Config[:shipment_inc_vat] %>
      <%= shipping_method[:name] %> <%= format_price (1 + Spree::TaxRate.default) * shipping_method[:cost] %>
    <% else %>
      <%= shipping_method[:name] %> <%= number_to_currency shipping_method[:cost] %>
    <% end %>
  </label>
<% end %>