fix(ninurta): remove unused postresql backup

nixos/modules/admin.nix

@@ -97,7 +97,7 @@ in
     services.openssh.openFirewall = true;
 
     users.users = mapAttrs (user: keys: {
-      shell = lib.mkDefault shells."${keys.shell}";
+      shell = shells."${keys.shell}";
       extraGroups = lib.mkDefault extraGroups;
       isNormalUser = true;
       openssh.authorizedKeys.keys = keys.keys;

nixos/ninurta/configuration.nix

@@ -149,13 +149,6 @@ in
     startAt = "daily";
   };
 
-  services.postgresqlBackup = {
-    enable = true;
-    backupAll = true;
-    compression = "zstd";
-    location = "/var/backup/postgresql";
-  };
-
   age.secrets."ninurta-backup-passphrase" = {
     file = "${secretsPath}/ninurta-backup-passphrase.age";
     mode = "400";