app/views/participant_challenges/_participant_challenges.html.erb
<% if @participant_challenges.blank? %>
<li>
<div class="details">
<h5>No participants yet...</h5>
</div>
</li>
<% else %>
<%= concept(ParticipantChallenge::Cell::ListDetail,
collection: @participant_challenges,
current_participant: current_participant) %>
<% end %>