app/components/form/error_message_component.html.erb
<div id="error_explanation">
<div class="alert alert-danger alert-dismissible fade show" role="alert">
<button type="button" class="close" data-dismiss="alert" aria-label="Close">
<span aria-hidden="true">×</span>
</button>
<span class="h6">The form contains <%= pluralize(object.errors.count, "error") %>.</span>
<ul style="margin-top: 1rem; margin-bottom: 0.5rem; padding-left: 1.3rem;">
<% object.errors.full_messages.each do |msg| %>
<li><%= msg %></li>
<% end %>
</ul>
</div>
</div>