Add builder user to hydra for remote building

config/hosts/hydra/configuration.nix

@@ -21,8 +21,18 @@
     };
   };
 
+  users.users.builder = {
+    isNormalUser = true;
+    openssh.authorizedKeys.keys = [
+      "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIKeIiHkHA5c6/jZx+BB28c5wchdzlFI7R1gbvNmPyoOg root@kiara"
+    ];
+  };
+
   nix = {
-    settings.allowed-uris = "http:// https://";
+    settings = {
+      trusted-users = [ "builder" ];
+      allowed-uris = "http:// https://";
+    };
     buildMachines = [
       {
         hostName = "localhost";