chore: add nix shell configuration

.vscode/settings.json

@@ -1,4 +1,5 @@
 {
-    "editor.formatOnSave": true,
-    "rust-analyzer.checkOnSave.command": "clippy"
-}
+  "editor.formatOnSave": true,
+  "rust-analyzer.checkOnSave.command": "clippy",
+  "nixEnvSelector.nixFile": "${workspaceRoot}/default.nix"
+}

default.nix

@@ -0,0 +1,33 @@
+let
+  # Pinned nixpkgs, deterministic. Last updated: 11-08-2023.
+  pkgs = import (fetchTarball("https://github.com/NixOS/nixpkgs/archive/bb9707ef2ea4a5b749b362d5cf81ada3ded2c53f.tar.gz")) {};
+
+  # Rolling updates, not deterministic.
+  # pkgs = import (fetchTarball("channel:nixpkgs-unstable")) {};
+in pkgs.mkShell {
+  name = "revoltEnv";
+
+  # LD_LIBRARY_PATH = pkgs.lib.makeLibraryPath [
+  #   pkgs.gcc-unwrapped
+  #   pkgs.zlib
+  #   pkgs.glib
+  #   pkgs.libGL
+  # ];
+
+  buildInputs = [
+    # Tools
+    pkgs.git
+
+    # Database
+    # pkgs.mongodb
+
+    # Rust
+    pkgs.cargo
+    pkgs.rustc
+    pkgs.clippy
+    pkgs.pkgconfig
+    pkgs.openssl.dev
+  ];
+
+  RUST_SRC_PATH = "${pkgs.rust.packages.stable.rustPlatform.rustLibSrc}";
+}