vergil: enable remotebuild service

hosts/vergil/configuration.nix

@@ -35,6 +35,16 @@ in
     };
   };
 
+  users.users."remotebuild" = {
+    isSystemUser = true;
+    group = "remotebuild";
+    useDefaultShell = true;
+    openssh.authorizedKeys.keyFiles = [ ./remotebuild.pub ];
+  };
+
+  users.groups.remotebuild = { };
+  nix.settings.trusted-users = [ "remotebuild" ];
+
   services = {
     nginx = {
       enable = true;