nixos/gitlab: fix hard-coded database name

nixos/modules/services/misc/gitlab.nix

@@ -619,7 +619,7 @@ in {
         fi
 
         # enable required pg_trgm extension for gitlab
-        ${pkgs.sudo}/bin/sudo -u ${pgSuperUser} psql gitlab -c "CREATE EXTENSION IF NOT EXISTS pg_trgm"
+        ${pkgs.sudo}/bin/sudo -u ${pgSuperUser} psql ${cfg.databaseName} -c "CREATE EXTENSION IF NOT EXISTS pg_trgm"
         # Always do the db migrations just to be sure the database is up-to-date
         ${gitlab-rake}/bin/gitlab-rake db:migrate RAILS_ENV=production