backwards: Share phone-gps with phone in syncthing

hosts/backwards/configuration.nix

@@ -3,6 +3,7 @@
   imports =
     [
       ../../config-manager/default.nix
+      ../../shared-modules/syncthing.nix
       ./hardware-configuration.nix
       ./modules
     ];

hosts/backwards/modules/syncthing/default.nix

@@ -11,6 +11,25 @@
     group = "users";
 
     dataDir = "/home/alex/sync";
+
+    settings = {
+      devices = {
+        phone.id = config.lib.syncthing.phone;
+      };
+
+      folders = {
+        "phone-gps" = {
+          path = "/home/alex/sync/phone-gps";
+          devices = [ "phone" ];
+          versioning = {
+            type = "staggered";
+            params = {
+              maxage = "2592000"; # 30 days
+            };
+          };
+        };
+      };
+    };
   };
 
   age = {