anchor.diff:  <% submissions.each do |submission| %>
     <tr id="submission-<%= submission.id %>" class='submission-row'>
  -    <td class="position"></td>
  +    <td></td>
  +    <td></td>
  +    <td class='change'></td>
  +    <td></td>
   
       <td class="participant">
         <div class="user-link">
  
positive.code:     <% end %>
  
      <td class="score">
        <strong><%= submission.score %></strong>
      </td>
  
      <% if cols.include?(:score_secondary) %>
        <td class="score">
          <strong><%= submission.score_secondary %></strong>
        </td>
      <% end %>
  
      <td class="entries">
        <%= submission.grading_status %>
        <% if policy(submission).destroy? %>
          <p class='status active'>
            <%= link_to 'delete',
                  challenge_submission_path(
                    submission.challenge,submission),
                  method: :delete,
                  data: {confirm: 'Are you sure?'} %>
          </p>
        <% end %>
      </td>
  
      <td class="last-submission">
        <%= submission.created_at.strftime("%a, %e %b %Y %R") %>
  
negative.code: 
      <td class='action'>
        <% if challenge.submissions_page %>
          <%= link_to challenge_submission_path(
                submission.challenge_id, submission.id),
                class: 'btn btn-secondary' do %>
                  <i class="fa fa-arrows-alt" aria-hidden="true"></i>
          <% end %>
        <% end %>
      </td>
  
    </tr>
  <% end %>
  