add snippet for nix flake

snippets/nix.snippets

@@ -13,3 +13,36 @@ snippet optionalAttrs
 snippet deps
   let pkgs = import <nixpkgs> {}; in
   with pkgs; [ $1 ]
+
+snippet flake
+  {
+    description = "Flake utils $1";
+    inputs = {
+      nixpkgs.url = "github:nixos/nixpkgs?ref=nixos-unstable";
+      flake-utils.url = "github:numtide/flake-utils";
+    };
+
+    outputs =
+      {
+        self,
+        nixpkgs,
+        flake-utils,
+      }:
+      flake-utils.lib.eachDefaultSystem (
+        system:
+        let
+          pkgs = nixpkgs.legacyPackages.\${system};
+        in
+        {
+          packages = rec {
+            $1 = pkgs.stdenv.mkDerivation {
+              name = "$1";
+              buildInputs = with pkgs; [
+                $2
+              ];
+            };
+            default = $1;
+          };
+        }
+      );
+  }