feat: add (incomplete) nix flake

dave.py isn't packaged yet. Will try to do this myself but dealing with
vcpkg is a bit annoying.

default.nix

@@ -0,0 +1,59 @@
+{
+  lib,
+  python3Packages,
+  self,
+  ...
+}:
+let
+  disnake = python3Packages.disnake.overrideAttrs (old: {
+    src = self.pins.disnake;
+
+    propagatedBuildInputs =
+      with python3Packages;
+      old.propagatedBuildInputs
+      ++ [
+        typing-extensions
+        versioningit
+      ];
+
+    nativeBuildInputs = old.nativeBuildInputs ++ [ python3Packages.hatchling ];
+  });
+
+  disnake_paginator = python3Packages.buildPythonPackage {
+    pname = "disnake-paginator";
+    version = "1.0.8";
+
+    src = self.pins.disnake-paginator;
+
+    pyproject = true;
+    build-system = [ python3Packages.setuptools ];
+
+    propagatedBuildInputs = [
+      disnake
+    ];
+
+    doCheck = false;
+  };
+in
+python3Packages.buildPythonApplication {
+  pname = "errornocord";
+  version = "0.1.0";
+
+  src = lib.cleanSource ./.;
+
+  pyproject = true;
+  build-system = [ python3Packages.setuptools ];
+
+  propagatedBuildInputs = with python3Packages; [
+    aiohttp
+    audioop-lts
+    disnake
+    disnake_paginator
+    psutil
+    typing-extensions
+    youtube-transcript-api
+    yt-dlp
+  ];
+
+  doCheck = false;
+}