treewide: impermanence configuration

modules/nixos/services/postgresql.nix

@@ -30,6 +30,15 @@ in
       };
     };
 
+    environment.persistence."/persist".directories = [
+      {
+        directory = "/var/lib/postgresql";
+        user = "postgres";
+        group = "postgres";
+        mode = "0700";
+      }
+    ];
+
     services.borgmatic.settings = {
       postgresql_databases = [
         {

modules/nixos/services/tailscale.nix

@@ -56,5 +56,9 @@ in
       trustedInterfaces = [ "tailscale0" ];
       allowedUDPPorts = [ config.services.tailscale.port ];
     };
+
+    environment.persistence."/state".directories = [
+      "/var/lib/tailscale"
+    ];
   };
 }