Add mac-demarco-mini syncthing config

nix-darwin/flake.nix

@@ -88,6 +88,7 @@
     sharedHomeModules = [
       ./home/common.nix
       ./home/git-sync.nix
+      ./home/syncthing.nix
     ];
     homeForUser = user: "/Users/${user}";
     configuration = {

nix-darwin/home/syncthing.nix

@@ -0,0 +1,37 @@
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}: let
+  shared = import ../../nix-shared/syncthing.nix;
+  inherit (shared) devices allDevices;
+in {
+  home.activation.ensureSyncthingDirectories = lib.hm.dag.entryAfter ["writeBoundary"] ''
+    /bin/mkdir -p "$HOME/Library/Logs/Syncthing" "$HOME/sync" "$HOME/railbird"
+  '';
+
+  services.syncthing = {
+    enable = true;
+    package = pkgs.syncthing;
+    settings = {
+      inherit devices;
+      folders = {
+        sync = {
+          path = "~/sync";
+          devices = allDevices;
+          ignorePerms = true;
+        };
+        railbird = {
+          path = "~/railbird";
+          devices = allDevices;
+          ignorePerms = true;
+        };
+      };
+      options = {
+        relaysEnabled = true;
+        localAnnounceEnabled = true;
+      };
+    };
+  };
+}