<fieldset>
  <legend>Which color do you prefer?</legend>
  <%= form_for :color do |f| %>
    <%= radio_button :color, :select, :red %> 
    <%= label :color, :select_red, 'Red' %>
    <%= radio_button :color, :select, :green %> 
    <%= label :color, :select_green, 'Green' %>
    <%= radio_button :color, :select, :blue %>
    <%= label :color, :select_blue, 'Blue' %>
  <% end %>
</fieldset>