draft: postgres in container

pkgs/backend.nix

@@ -1,3 +1,34 @@
-{}:
+{ pkgs, hexname-backend, ... }:
 
+{
+  nixpkgs.overlays = [
+    (self: super: {
+      hexname-backend = hexname-backend.packages.${super.stdenv.hostPlatform.system}.default;
+    })
+  ];
+
+  users.groups.hexname = {};
+  users.users = {
+    hexname-backend = {
+      group = "hexname";
+      isSystemUser = true;
+      createHome = true;
+      home = "/var/lib/hexname/backend";
+    };
+  };
+
+  systemd.services.hexname-backend = {
+    after = [ "network.target" ];
+    wantedBy = [ "multi-user.target" ];
+    environment = {
+      ENV_PATH = "/etc/env/hexname/backend.env";
+    };
+    serviceConfig = {
+      User = "hexname-backend";
+      Group = "hexname";
+      Type = "simple";
+      ExecStart = "${pkgs.hexname-backend}/bin/dns-backend";
+    };
+  };
+}