gutterman: add restic backups to minecraft

modules/nixos/services/gameserver/restic.nix

@@ -0,0 +1,31 @@
+{ config, pkgs, ... }:
+
+{
+  sops.secrets = {
+    "restic/password" = {};
+    "restic/rest-auth.env" = {};
+  };
+
+  services.restic.backups.gameservers =
+  assert config.users.users.restic-backup != null;
+  {
+    user = "restic-backup";
+    package = pkgs.writeShellScriptBin "restic" ''
+      exec /run/wrappers/bin/restic "$@"
+    '';
+
+    initialize = true;
+    repository = "rest:https://restic.taild5f7e6.ts.net/gutterman/gameservers";
+    environmentFile = config.sops.secrets."restic/rest-auth.env".path;
+    passwordFile = config.sops.secrets."restic/password".path;
+    timerConfig = {
+      OnCalendar = "03:00";
+      Persistent = true;
+    };
+
+    paths = [
+      "/var/lib/minecraft"
+    ];
+    exclude = [ ".*" ];
+  };
+}