tracktrain: upstream is slow in updating gtfs, use our own

note: I am author of both the file now under /persist/containers/tracktrain
& the upstream one at ilztalbahn.eu, but don't have direct access to the
wordpress instance running there, and no one who does has yet uploaded
the new file.

services/tracktrain.nix

@@ -3,7 +3,7 @@
 let
   tracktrain-config = ''
     dbstring: "dbname=tracktrain"
-    gtfs: ./gtfs.zip
+    gtfs: /persist/gtfs.zip
     assets: ${pkgs.tracktrain}/assets
 
     warp:
@@ -73,7 +73,7 @@ in
         after = [ "network.target" ];
         serviceConfig = {
           Type = "simple";
-          EnvironmentFile = "/persist/secrets.env";
+          EnvironmentFile = "/secrets/env";
           User = "tracktrain";
           Group = "tracktrain";
         };