added nix stuffs

.envrc

@@ -0,0 +1 @@
+use nix

shell.nix

@@ -0,0 +1,10 @@
+{ pkgs ? import <nixpkgs> {} }:
+
+with pkgs;
+
+mkShell {
+  name = "blog";
+  buildInputs = [
+    hugo
+  ];
+}