base/base.nix: set hostname in base module using nix opt

base/base.nix

@@ -1,5 +1,5 @@
 # Module: base/base
-{ config, lib, pkgs, ... }:
+{ config, hostName, lib, pkgs, ... }:
 
 with lib;
 
@@ -14,11 +14,20 @@ in {
         "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAILiUy2yjIkdryH7pYMdkCNryy9gceqXJ7bhtMvvpPBIk etorres@xenon"
       ];
     };
+
+    hostName = mkOption {
+      type = types.str;
+      default = "nixOS";
+      description = "System's hostname";
+      example = "server-01";
+    };
   };
 
   imports = [ ./grafana-alloy.nix ./network.nix ./qemu.nix ./spice.nix ];
 
   config = {
+    networking.hostName = cfg.hostName;
+
     time.timeZone = "Etc/UTC";
 
     i18n.defaultLocale = "en_US.UTF-8";