explorer_app/app/views/shared/_breadcrumbs.html.erb
<nav aria-label="breadcrumb">
<ol class="breadcrumb mt-2">
<% links.each do |label, url| %>
<li class="breadcrumb-item">
<%= link_to label, url %>
</li>
<% end %>
<li class="breadcrumb-item active" aria-current="page"">
<%= active_label %>
</li>
</ol>
</nav>