app/views/authors_sidebar/_content.html.erb
<% cache sidebar.authors do %>
<% unless sidebar.authors.blank? %>
<h3 class="sidebar-title"><%= t('.authors') %></h3>
<div class="sidebar-body">
<ul id="categories">
<% for user in sidebar.authors %>
<li>
<% count = "(#{user.articles.count})" %>
<%= link_to "#{h(user.name)} #{count if sidebar.count}", author_path(id: user.login) %>
</li>
<% end %>
</ul>
</div>
<% end %>
<% end %>