anchor.diff:      db_cast_list_path(work),
       class: "nav-link",
       class_active: "active",
  -    active: params[:controller]  == "db/casts"
  +    active: params[:controller]  == "v4/db/casts"
     ) %>
   
     <%= active_link_to(
  
positive.code:       db_slot_list_path(work),
        class: "nav-link",
        class_active: "active",
        active: params[:controller]  == "db/slots"
      ) %>
    <% end %>
  
  
negative.code:     db_trailer_list_path(work),
      class: "nav-link",
      class_active: "active",
      active: params[:controller]  == "v4/db/trailers"
    ) %>
  </ul>
  