We need Rails in order to use Gitlab.config anyway

bin/upgrade.rb

-require_relative "../lib/gitlab/upgrader"
+require_relative '../config/environment'
 
 Gitlab::Upgrader.new.execute

lib/gitlab/upgrader.rb

-require_relative "popen"
-require_relative "version_info"
-
 module Gitlab
   class Upgrader
     def execute