fix user_signed_in verification in user show

app/views/users/show.html.erb

@@ -14,7 +14,7 @@
           </div>
         </div>
         <div class="col-md-6 right-column align-right">
-          <% if user_exists? and current_user_page? @user %>
+          <% if user_signed_in? && current_user_page? @user %>
             <%= link_to 'Adicionar novo objeto', new_learning_object_path, class: 'btn btn-primary'%>
           <% else %>
               <!-- <button type="button" class="btn btn-primary">Enviar mensagem</button> -->
@@ -48,7 +48,7 @@
         </div>
       </div>
       <div class="col-md-6 right-column align-right">
-        <%= render('collections/create', collection: @new_collection, publishers: @publishers, placement: 'left') if user_exists? and current_user_page?(@user) %>
+        <%= render('collections/create', collection: @new_collection, publishers: @publishers, placement: 'left') if user_signed_in? && current_user_page?(@user) %>
       </div>
     </div>