anchor.diff:    <li><%= link_to t('.about'), about_path %></li>
     <li><%= link_to t('.help'), help_path %></li>
     <li><a href="https://www.coursera.org/course/techcity"><%= t '.technicity' %></a></li>
  -  
  +  <!--  
     <li><%= link_to t('.public_studies'), studies_path %></li>
     <% if user_signed_in? %>
       <!-- MF - placeholder -->
  
positive.code:   
  </ul>
  <%= link_to "Sign up", new_user_registration_path %>
  -->
negative.code:   <% else %>
      <li><%= link_to t('.login'), new_user_session_path %></li>
    <% end %>
    --> 
  </ul>
  
  
  