lpr-partynest/app/views/application/_flash.html.erb

<% unless flash.empty? %>
  <div class="container">
    <% flash.select { |_, msg| msg.is_a? String }.each do |type, msg| %>
      <div class="alert <%= bootstrap_class_for_flash type %> alert-dismissable fade show mt-3">
        <%= msg %>
        <button class="close" data-dismiss="alert">x</button>
      </div>
    <% end %>
  </div>
<% end %>