Fix package

default.nix

@@ -1,7 +1,7 @@
-{ pkgs ? import <nixpkgs> {} }:
-pkgs.stdenv.mkDerivation rec {
+{ stdenv, pandoc }:
+stdenv.mkDerivation rec {
   src = ./src;
-  nativeBuildInputs = [ pkgs.pandoc ];
+  nativeBuildInputs = [ pandoc ];
   buildPhase = ''
     find . -iname "*.md" -type f -exec sh -c 'pandoc -s -f commonmark -t html --template template.html -o "''${0%.md}.html" "''${0}"' {} \;
   '';

shell.nix

@@ -0,0 +1,6 @@
+{ pkgs ? import <nixpkgs> {} }:
+
+with pkgs;
+{
+  this = callPackage ./default.nix { };
+}