tweaks to audiobookshelf

modules/audiobookshelf.nix

@@ -1,16 +1,20 @@
 { pkgs, lib, config, ... }:
 
 with lib;
+
+let
+  port = "8999";
+
 {
   services.audiobookshelf = {
     enable = true;
     host = "0.0.0.0";
-    port = "8999";
+    port = port;
   };
 
   services.caddy.virtualHosts = {
       "abs.cochrun.xyz".extraConfig = ''
-        reverse_proxy localhost:${services.audiobookshelf.port}
+        reverse_proxy localhost:${port}
       '';
   };
 }