app/views/layouts/_navigation_links.html.erb
<%# add navigation links to this file %>
<% if user_signed_in? %>
<li><%= link_to_unless_current t('application.navigation.dashboard'), dashboard_path %></li>
<li><%= link_to_unless_current t('application.navigation.sign_out'), destroy_user_session_path, :method=>'delete' %></li>
<% else %>
<li><%= link_to_unless_current t('application.navigation.sign_in'), new_user_session_path(previous_url: request.path) %></li>
<% end %>