Added more tools

roles/nixpkgs-dev.nix

@@ -13,9 +13,12 @@
   environment = {
     systemPackages = with pkgs; [
       cabal2nix                # Convert Cabal files into Nix build instructions
+      nix-prefetch-github      # Prefetch sources from github
+      nix-prefetch-git         # Prefetch sources from git
       nix-review               # Review pull-requests on https://github.com/NixOS/nixpkgs
       nix-universal-prefetch   # Uses nixpkgs fetchers to figure out hashes
       nodePackages.node2nix    # Generate Nix expressions to build NPM packages
+      nox                      # Tools to make Nix nicer
     ];
   };