Merge pull request 'Adding direnv and nix support' (#7) from feature/direnv-and-nix into dev

Reviewed-on: #7

.envrc

@@ -0,0 +1,4 @@
+# if nix is installed and dotenv allowed in dir, use it to pull dependencies
+if has nix; then
+  use nix
+fi

shell.nix

@@ -0,0 +1,5 @@
+{ pkgs ? import <nixpkgs> {} }:
+pkgs.mkShell {
+  name = "afrapay";
+  packages = with pkgs; [ dotnet-sdk_7 ];
+}