app/views/categories/_links.html.erb
<% if user_signed_in? %>
<hr />
<ul class="unstyled">
<% if controller.action_name == 'show' %>
<li>
<%= link_to edit_category_path(@category) do %>
<i class="icon-pencil"></i> <%= t(:edit_category) %>
<% end %>
</li>
<% end %>
<li>
<%= link_to :new_category do %>
<i class="icon-plus"></i> <%= t(:new_category) %>
<% end %>
</li>
<% unless current_page?(action: :index) %>
<li>
<%= link_to :categories do %>
<i class="icon-folder-open-alt"></i> <%= t(:list_categories) %>
<% end %>
</li>
<% end %>
</ul>
<% end %>