Each :notice :error :alert helper

application.html.erb

<% [:notice, :error, :alert].each do |level| %>
  <% unless flash[level].blank? %>
    <div data-alert="alert" class="alert alert-<%= flash_class(level) %> fade in">
      <a class="close" data-dismiss="alert" href="#">&times;</a>
      <%= content_tag :p, flash[level] %>
    </div>
  <% end %>
<% end %>

application_helper.rb

module ApplicationHelper
  def flash_class(level)
    case level
      when :notice then 'info'
      when :error then 'error'
      when :alert then 'warning'
    end
  end
end