flake update and add btop to work machine

systems/modules/btop.nix

@@ -0,0 +1,8 @@
+{ config, pkgs, ... }:
+
+{
+  environment.systemPackages = with pkgs; [
+    btop
+  ];
+}
+

systems/work/default.nix

@@ -24,6 +24,7 @@
       ../modules/enova.nix
       ../modules/devenv.nix
       ../modules/bitwarden.nix
+      ../modules/btop.nix
     ];
 
   boot.kernelPackages = pkgs.linuxPackages_latest;