Update zerotierone.nix

Added option to write zerotier's local.conf in nix.

nixos/modules/services/networking/zerotierone.nix

@@ -28,7 +28,20 @@ in
   };
 
   options.services.zerotierone.package = mkPackageOption pkgs "zerotierone" { };
-
+	
+  options.services.zerotierone.localConf = mkOption {
+			default = { };
+			description = mdDoc ''
+				Configuration to be written to the zerotier JSON-based local.conf.
+				The configuration will be symlinked to /var/lib/zerotier-one/local.conf at build time.
+				To understand the configuration format, refer to https://docs.zerotier.com/config/#local-configuration-options.
+			'';
+			example = {
+				settings.allowTcpFallbackRelay = false;
+			};
+			type = types.attrs;
+	};
+  
   config = mkIf cfg.enable {
     systemd.services.zerotierone = {
       description = "ZeroTierOne";
@@ -45,7 +58,9 @@ in
         chown -R root:root /var/lib/zerotier-one
       '' + (concatMapStrings (netId: ''
         touch "/var/lib/zerotier-one/networks.d/${netId}.conf"
-      '') cfg.joinNetworks);
+      '') cfg.joinNetworks) + ''
+				ln -s ${conf} /var/lib/zerotier-one/local.conf
+			'';
       serviceConfig = {
         ExecStart = "${cfg.package}/bin/zerotier-one -p${toString cfg.port}";
         Restart = "always";