app/views/marcas/edit.html.erb
<%= content_for :nav do%>
<%= render "layouts/navbar" %>
<% end %>
<div class = "container-box">
<h2 class = "color-font"><center>Editar Marca</center></h2>
<%= render 'form', marca: @marca %>
<%= link_to 'Mostrar', @marca %> |
<%= link_to 'Voltar', marcas_path %>
</div>