app/views/layouts/admin/_messages.html.erb
<%# Rails flash messages styled for Bootstrap 3.0 %>
<% flash.each do |name, msg| %>
<% if msg.is_a?(String) %>
<div class="alert alert-<%= name.to_s == 'notice' ? 'success' : 'danger' %>">
<button type="button" class="close" data-dismiss="alert" aria-hidden="true">×</button>
<%= content_tag :div, msg, :id => "flash_#{name}" %>
</div>
<% end %>
<% end %>