users: Add system.singleUser

modules/programs/emacs/default.nix

@@ -1,7 +1,7 @@
-{ ... }:
+{ config, ... }:
 
 {
-  home-manager.users.alexander.home.file = {
+  config.home-manager.users."${config.system.singleUser}".home.file = {
     ".emacs".source = ./dotemacs;
     ".emacs.d/early-init.el".source = ./early-init.el;
     ".emacs.d/mu4e.el".source = ./mu4e.el;