add bare metal runtime

.devcontainer/devcontainer.json

@@ -1,7 +1,12 @@
 {
 	"name": "Alpine",
 	"image": "mcr.microsoft.com/devcontainers/base:alpine",
-	"postCreateCommand": "sudo apk add nix nix-dev nix-doc nix-manual nix-bash-completion && sudo chown -R vscode:vscode /nix && echo 'experimental-features = nix-command flakes' | sudo tee -a /etc/nix/nix.conf",
+	"features": {
+		"ghcr.io/devcontainers/features/nix:1": {
+			"extraNixConfig": "experimental-features = nix-command flakes",
+			"packages": "nixpkgs-fmt"
+		}
+	},
 	"runArgs": [
 		"--userns=keep-id"
 	],