Add auto-upgrade module

clanModules/auto-upgrade/README.md

@@ -0,0 +1,8 @@
+---
+description = "Set up automatic upgrades"
+categories = ["System"]
+features = [ "inventory" ]
+---
+
+Whether to periodically upgrade NixOS to the latest version. If enabled, a
+systemd timer will run `nixos-rebuild switch --upgrade` once a day.

clanModules/auto-upgrade/roles/default.nix

@@ -0,0 +1,24 @@
+{
+  config,
+  lib,
+  ...
+}:
+let
+  cfg = config.clan.autoUpgrade;
+in
+{
+  options.clan.autoUpgrade = {
+    flake = lib.mkOption {
+      type = lib.types.str;
+      description = "Flake reference";
+    };
+  };
+  config = {
+    system.autoUpgrade = {
+      inherit (cfg.clan.autoUpgrade) flake;
+      enable = true;
+      dates = "02:00";
+      randomizedDelaySec = "45min";
+    };
+  };
+}