photomix/app/views/collections/index.html.erb

<% @collections.in_groups_of(4).compact.each do |group| %>
    <% unless group.compact.empty? %>
        <ul class="thumbnails">
          <% group.compact.each do |collection| %>
              <% unless collection.albums.empty? %>
                  <% unless collection.albums.first.photos.empty? %>
                      <li class="span3">
                        <div class="thumbnail">
                          <%= image_tag collection.albums.first.photos.first.attachment.collection.url %>
                          <div class="caption">
                            <h5><%= collection.title %></h5>
                            <p><%= collection.description %></p>
                            <p><%= link_to 'View', (collection_path(collection) unless collection.albums.empty? || collection.albums.first.photos.empty?), {:class => 'btn btn-primary'} %></p>
                          </div>
                        </div>
                      </li>
                  <% end %>
              <% end %>
          <% end %>
        </ul>
    <% end %>
<% end %>


<%= content_for :action_links do %>
    <% if current_user and current_user.has_role?("admin") %>
        <%= link_to "New collection", new_collection_path %>
    <% end %>
<% end %>