nixos/redis: set config group for service user

Avoids trying to set the primary group of the redis user to a group that doesn't exist.

Signed-off-by: Julia DeMille <me@jdemille.com>
Change-Id: Ic67fb735ca739a13b95e98675994de376a6a6964

nixos/modules/services/databases/redis.nix

@@ -477,7 +477,7 @@ in
       lib.nameValuePair (redisName name) {
         description = "System user for the redis-server instance ${name}";
         isSystemUser = true;
-        group = redisName name;
+        group = conf.group;
       }
     ) (lib.filterAttrs (name: conf: conf.user == redisName name) enabledServers);
     users.groups = lib.mapAttrs' (