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