scinote-web/app/views/activities/_list.html.erb

<%
  current_day = days_since_1970(DateTime.current)
%>
<% if !hide_today && activities.count > 0 && days_since_1970(activities[0].created_at) == current_day %>
  <li class="text-center activity-date-item">
    <span class="label label-primary">
      <%=t "activities.index.today" %>
    </span>
  </li>
<% end %>
<% activities.each do |activity| %>
  <% activity_day = days_since_1970(activity.created_at) %>

  <% if activity_day < current_day and activity_day < day %>
    <% day = days_since_1970(activity.created_at) %>
    <li class="text-center activity-date-item">
      <span class="label label-primary">
        <%= activity.created_at.strftime('%d.%m.%Y') %>
      </span>
    </li>
  <% end %>
  <%= render 'activities/activity.html.erb', activity: activity %>
<% end %>