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.

flake.nix

@@ -0,0 +1,41 @@
+{
+  inputs = {
+    flake-parts.url = "github:hercules-ci/flake-parts";
+
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+  };
+
+  outputs =
+    {
+      flake-parts,
+      self,
+      ...
+    }@inputs:
+    flake-parts.lib.mkFlake { inherit inputs; } {
+      systems = [
+        "aarch64-linux"
+        "x86_64-linux"
+      ];
+
+      perSystem =
+        { pkgs, self', ... }:
+        {
+          devShells.default = pkgs.mkShell {
+            name = "errornocord";
+
+            buildInputs = [
+              self'.packages.default
+            ];
+          };
+
+          packages = rec {
+            errornocord = pkgs.callPackage ./. { inherit self; };
+            default = errornocord;
+          };
+        };
+
+      flake.pins = import ./npins;
+    };
+
+  description = "Hot-reloadable Discord music bot";
+}