Merge pull request 'Add hidden class when sign_up_overdue.' (#19) from 123/seminar:master into master

Reviewed-on: https://gitlab.tp.rulingcom.com/spen/seminar/pulls/19

app/views/seminars/show_data.html.erb

@@ -50,7 +50,7 @@
       <td class="seminarive-title-value"><%= @contribute_time_range %></td>
     </tr>
     <% end %>
-    <tr <%= 'class="hidden"' if @sign_up_overdue %>>
+    <tr <%= 'class="hidden"'.html_safe if @sign_up_overdue && @contribute_action.blank? %>>
       <th class="seminarive-title-field"><%= t('seminar.signup') %></th>
       <td class="seminarive-title-value"><%= @sign_up %><br /><%= @contribute_action %></td>
     </tr>