small change

modules/default.nix

@@ -1,4 +1,9 @@
-{...}: {
+{
+  lib,
+  ...
+}: let
+  inherit (lib) mkOption types;
+in {
   imports = [
     ./apps
     ./hardware
@@ -10,4 +15,10 @@
     ./timers
     ./username.nix
   ];
+
+  options = {
+    horseman = {
+      username = mkOption {type = types.str;};
+    };
+  };
 }

modules/username.nix

@@ -1,9 +0,0 @@
-{lib, ...}: let
-  inherit (lib) mkOption types;
-in {
-  options = {
-    horseman = {
-      username = mkOption {type = types.str;};
-    };
-  };
-}