Add development environment using Nix flakes

.envrc

@@ -0,0 +1 @@
+use flake

.gitignore

@@ -63,3 +63,6 @@ dist/
 .next
 .DS_Store
 /.vscode
+
+# Direnv
+.direnv/

flake.nix

@@ -0,0 +1,44 @@
+{
+  inputs = {
+    flake-parts.url = "github:hercules-ci/flake-parts";
+    nix-packages.url = "github:nixos/nixpkgs/nixpkgs-unstable";
+    nix-systems.url = "github:nix-systems/default";
+  };
+  outputs = inputs @ {
+    flake-parts,
+    nix-packages,
+    nix-systems,
+    ...
+  }: let
+    packagesModule = {
+      perSystem = {system, ...}: {
+        _module.args.packages = import nix-packages {
+          inherit system;
+        };
+      };
+    };
+
+    systemsModule = {
+      systems = import nix-systems;
+    };
+  in
+    flake-parts.lib.mkFlake {inherit inputs;} {
+      imports = [
+        packagesModule
+        systemsModule
+      ];
+
+      perSystem = {packages, ...}: {
+        devShells.default = packages.mkShell {
+          nativeBuildInputs = with packages; [
+            # Nix
+            alejandra
+            nil
+
+            # Node
+            nodejs
+          ];
+        };
+      };
+    };
+}