Add remote builder to laptop

hosts/froidmpa-laptop/default.nix

@@ -50,5 +50,27 @@
       ];
     };
   };
+
+  nix = {
+    distributedBuilds = true;
+    buildMachines = [
+      {
+        hostName = "hel1.banditlair.com";
+        sshUser = "nix-ssh";
+        system = "x86_64-linux";
+        supportedFeatures = [
+          "nixos-test"
+          "benchmark"
+          "big-parallel"
+          "kvm"
+        ];
+      }
+    ];
+    settings = {
+      substituters = [ "ssh://nix-ssh@hel1.banditlair.com" ];
+      trusted-public-keys = [ "hel1.banditlair.com:stzB4xe5QTFvSABoP11ZpNzLDCRZ93PExk0Z/gOzW3g=" ];
+      builders-use-substitutes = true;
+    };
+  };
   system.stateVersion = "21.05";
 }