anchor.diff:  <div class="block block-alternate">
     <h2>Sponsors</h2>
   </div>
  +
   
   <div class="block">
     <h2>Attendees</h2>
  
positive.code: 
  <%= render 'block_location' %>
  
  <div class="block">
    <h2>Itinerary</h2>
  </div>
  
negative.code:   <% else %>
      <p>No one has signed up yet...</p>
    <% end %>
  </div>
  
  -->