tap/app/views/application/_flash.html.erb

<div id="flash">
  <% if flash[:error] %>
    <div class="alert alert-danger alert-dismissable">
      <button type="button" class="close" data-dismiss="alert" aria-hidden="true">&times;</button>
      <strong>Error!</strong> <%= flash[:error] %>
    </div>
  <% end %>
  <% if flash[:success] %>
    <div class="alert alert-success alert-dismissable">
      <button type="button" class="close" data-dismiss="alert" aria-hidden="true">&times;</button>
      <strong>Success!</strong> <%= raw flash[:success] %>
    </div>
  <% end %>
  <% if flash[:notice] %>
    <div class="alert alert-info alert-dismissable">
      <button type="button" class="close" data-dismiss="alert" aria-hidden="true">&times;</button>
      <strong>Notice!</strong> <%= flash[:notice] %>
    </div>
  <% end %>
  <% if flash[:warning] %>
    <div class="alert alert-warning alert-dismissable">
      <button type="button" class="close" data-dismiss="alert" aria-hidden="true">&times;</button>
      <strong>Warning!</strong> <%= flash[:warning] %>
    </div>
  <% end %>
</div>