multi-user toggle init

modules/shell/config.nix

@@ -14,7 +14,11 @@
     description = "The shell to use system-wide (bash or zsh)";
   };
   config = {
-    users.users.jawz.shell = pkgs.${config.my.shell.type};
+    users.users = let
+      users = if lib.isString config.my.toggleUsers.shell then [ config.my.toggleUsers.shell ] else config.my.toggleUsers.shell;
+    in lib.mkMerge (map (user: {
+      ${user}.shell = pkgs.${config.my.shell.type};
+    }) users);
     programs.zsh.enable = config.my.shell.type == "zsh";
   };
 }