aplysia: use new users.users attribute

aplysia.nix

@@ -29,15 +29,21 @@ in
     hostId = "34a820f1";
   };
 
-  users.extraUsers.gebner.extraGroups = [
+  users = {
+    users = {
+      gebner.extraGroups = [
         "transmission"
         "nilotica"
       ];
 
-  users.extraUsers.nilotica = {
+      nilotica = {
-    extraGroups = [
+        group = "nilotica";
-      "nilotica"
+      };
-    ];
+    };
+
+    groups = {
+      nilotica = {};
+    };
   };
 
   boot.kernelPackages = pkgs.lib.mkOverride 10 pkgs.linuxPackages;