feat: add nix shell (#121)

Signed-off-by: Amy <amy+git@amogus.cloud>

Author: amycatgirl

default.nix

@@ -0,0 +1,19 @@
+{
+  pkgs ? import <nixpkgs> { },
+}:
+
+with pkgs;
+pkgs.mkShell {
+  name = "stoatEnv";
+
+  buildInputs = [
+    # Tools
+    git
+    gh
+    deno
+
+    # Node
+    nodejs
+    nodejs.pkgs.pnpm
+  ];
+}