add demo configs

app/controllers/application_controller.rb

@@ -4,6 +4,7 @@ class ApplicationController < ActionController::Base
   include ActiveStorage::SetCurrent
   include Pagy::Backend
 
+  before_action :sign_in_for_demo, if: -> { Docuseal.demo? }
   before_action :maybe_redirect_to_setup, unless: :signed_in?
   before_action :authenticate_user!, unless: :devise_controller?
 
@@ -21,6 +22,10 @@ class ApplicationController < ActionController::Base
 
   private
 
+  def sign_in_for_demo
+    sign_in(User.first) unless signed_in?
+  end
+
   def current_account
     current_user&.account
   end