app/views/layouts/partials/_callouts.html.erb
<% flash.each do |flash_type, flash_message| %>
<div id="messages" class="callout <%= flash_type %>" data-closable='hinge-out-from-top'>
<%= flash_message %>
<button class="close-button" aria-label="Dismiss alert" type="button" data-close>
<span aria-hidden="true">×</span>
</button>
</div>
<% end %>