tracktrain: add a delay so postgres has time to start

parsons/tracktrain.nix

@@ -65,10 +65,13 @@ in
         script = ''
           cd /tmp
           ln -sf ${pkgs.writeText "tracktrain-config.yaml" tracktrain-config} config.yaml
+          sleep 3
           ${pkgs.tracktrain}/bin/tracktrain +RTS -T
         '';
       };
 
+      systemd.services.postgresql.wantedBy = [ "tracktrain.service" ];
+
       services.postgresql = {
         enable = true;
         package = pkgs.postgresql_15;