application_controller.rb

  def store_location
    # store last url - this is needed for post-login redirect to whatever the user last visited.
    unless (sign_in_url =~ request.path ||
        sign_up_url =~ request.path ||
        user_confirmation =~ request.path ||
        sign_password =~ request.path ||
        cookies_allow =~ request.path ||
        request.xhr?) # don't store ajax calls
      session[:previous_url] = request.path
    end
  end