adding custom flash attribute in rails 4 for bootstrap and foundation

class ApplicationController < ActionController::Base
 # ...
 add_flash_types :error, :success
end

if using bootstrap then use this

add_flash_types :error, :success, :info 

if using foundation then use this

add_flash_types :success :secondary 

using it with controller

class UsersController < ApplicationController
 #...
 def create
 @user = User.new(user_params)
 if @user.save
 redirect_to @user, success: "User created!"
 else
 render :new
 end
 end
end

You will need a flash helper like this

#/app/view/layouts/application.html.erb
<% flash.each do |key, value| %>
 <div class="flash <%= key %>">
 <%= value %>
 </div>
<% end %>

for bootstrap use this

<% flash.each do |key, value| %>
 <div class="flash <%= "alert alert-#{key}" %>">
 <%= value %>
 </div>
<% end %>