app/views/projects/_activities_group.html.erb
<% activities_group.reverse_each do |date_group| %>
<ul class="timeline-day">
<li class="activities-date">
<%= l date_group.first.to_date, format: :short %>
</li>
<ul class="project">
<% date_group.last.each do |project_group| %>
<li class="activities-project">
<%= link_to project_group.first.name, project_path(project_group.first), class: 'project-link' %>
</li>
<ul class="subjects">
<% project_group.last.each do |activities| %>
<% activities.last.reverse.each do |activity| %>
<% if activity.description %>
<li class="activities-subject">
<i class="timeline-circle"></i>
<div class="subject">
<small><%= activity.created_at.strftime("%H:%M") %></small><br>
<%= activity.description.html_safe %>
</div>
</li>
<% end %>
<% end %>
<% end %>
</ul>
<% end %>
</ul>
</ul>
<% end %>