nixos/shout: define group, fix eval after #133166

nixos/modules/misc/ids.nix

@@ -237,7 +237,7 @@ in
       riemanntools = 203;
       subsonic = 204;
       riak = 205;
-      shout = 206;
+      #shout = 206; # dynamically allocated as of 2021-09-18
       gateone = 207;
       namecoin = 208;
       #lxd = 210; # unused

nixos/modules/services/networking/shout.nix

@@ -83,11 +83,13 @@ in {
 
   config = mkIf cfg.enable {
     users.users.shout = {
-      uid = config.ids.uids.shout;
+      isSystemUser = true;
+      group = "shout";
       description = "Shout daemon user";
       home = shoutHome;
       createHome = true;
     };
+    users.groups.shout = {};
 
     systemd.services.shout = {
       description = "Shout web IRC client";