Set up shell.nix direnv

.envrc

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+use nix

shell.nix

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+# <shell.nix>
+{ pkgs ? import <nixpkgs> {}}:
+
+let
+  rust_overlay = import (builtins.fetchTarball "https://github.com/oxalica/rust-overlay/archive/master.tar.gz");
+  pkgs = import <nixpkgs> { overlays = [ rust_overlay ]; };
+  ruststable = (pkgs.rust-bin.stable.latest.default.override {
+    extensions = [
+      "rust-src"
+    ];
+  });
+in
+pkgs.mkShell {
+  buildInputs = with pkgs; [
+    ruststable
+    rust-analyzer
+    bacon
+    pkg-config
+    openssl
+  ];
+}