in_groups_of example. bootstrap row class every third

gistfile1.rb

    <div class="span6">
      <h3><%= link_to "Background Images", bgimages_path %></h3>
      <% @bgimages.in_groups_of(3, false) do |bgimage_rows| %>
        <div class="row">
          <% for bgimage in bgimage_rows %>
            <div class="span2 text-left">
              <a href="<%= bgimage.bgimagefile.url %>"><img class="bgimagethumb img-polaroid" src="<%= bgimage.bgimagefile.url(:thumb) %>" /></a>
            </div>
          <% end %>
        </div>
      <% end %>
    </div>
  </div>