add hugo flake

flake-hugo.nix

@@ -0,0 +1,19 @@
+{
+  description = "A flake for publishing blog posts to https://blog.adityakumar.xyz/";
+
+  inputs.nixpkgs.url = "github:nixos/nixpkgs/23.05";
+
+  outputs = { self, nixpkgs }: {
+    packages.x86_64-linux.default = with import nixpkgs { system = "x86_64-linux"; };
+    stdenv.mkDerivation {
+        name = "blog";
+        buildInputs = [
+        pkgs.hugo
+        pkgs.rsync
+        ];
+        src = self;
+        buildPhase = "hugo server";
+        installPhase = "./deploy.sh";
+      };
+  };
+}