adds config for actual server

modules/actual-server/default.nix

@@ -0,0 +1,18 @@
+{
+  pkgs,
+  ...
+}:
+{
+  systemd.user.services.actual-server = {
+    enable = true;
+    after = [ "network.target" ];
+    wantedBy = [ "multi-user.target" ];
+    description = "user service for the actual budgeting server instance";
+    serviceConfig = {
+      type = "simple";
+      ExecStart = "ACTUAL_PORT=9002 ${pkgs.actual-server}";
+      Restart = "on-failure";
+      RestartSec = 3;
+    };
+  };
+}