Apply Postgres force-restore patch

config/patches/gitlab-rails/pg_force_restore.patch

+diff --git a/lib/backup/database.rb b/lib/backup/database.rb
+index ebb4f28..6552f45 100644
+--- a/lib/backup/database.rb
++++ b/lib/backup/database.rb
+@@ -29,6 +29,8 @@ module Backup
+         print "Restoring MySQL database #{config['database']} ... "
+         system('mysql', *mysql_args, config['database'], in: db_file_name)
+       when "postgresql" then
++        puts "Destructively rebuilding database schema for RAILS_ENV #{Rails.env}"
++        Rake::Task["db:schema:load"].invoke
+         print "Restoring PostgreSQL database #{config['database']} ... "
+         pg_env
+         system('psql', config['database'], '-f', db_file_name)

config/software/gitlab-rails.rb

@@ -54,6 +54,10 @@ build do
   # Patch the gitlab backup script to correctly restore gitlab-shell hooks
   patch :source => "backup_restore_hooks.patch"
+  # The backup script in gitlab-rails 6-6-stable fails to overwrite existing
+  # Postgres data. This patch, taken from gitlab-rails master, fixes that.
+  patch :source => "pg_force_restore.patch"
+
   bundle "install --without mysql development test --path=#{install_dir}/embedded/service/gem", :env => env
   # In order to precompile the assets, we need to get to a state where rake can