chore: add envrc and shell.nix
diff --git a/shell.nix b/shell.nix
new file mode 100644
index 0000000..28966f9
--- /dev/null
+++ b/shell.nix
@@ -0,0 +1,7 @@
+{ pkgs ? import <nixpkgs> { } }:
+
+pkgs.mkShell {
+  packages = with pkgs; [
+    pkgs.poetry
+  ];
+}