chore: add nix flake

Author: not-matthias

.envrc

@@ -0,0 +1 @@
+use flake

flake.lock

@@ -0,0 +1,30 @@
+{
+  description = "A Go development environment for codspeed-go";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs = {
+    self,
+    nixpkgs,
+    flake-utils,
+  }:
+    flake-utils.lib.eachDefaultSystem (
+      system: let
+        pkgs = import nixpkgs {inherit system;};
+      in {
+        devShells.default = pkgs.mkShell {
+          buildInputs = with pkgs; [
+            pre-commit
+
+            go
+            gopls
+            gotools
+            go-tools
+          ];
+        };
+      }
+    );
+}