add nix setups

.envrc

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

.gitignore

@@ -17,4 +17,5 @@ Cargo.lock
 .vscode/
 .idea/
 
-*.dot
+*.dot
+.direnv

flake.nix

@@ -0,0 +1,32 @@
+{
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    flake-utils.url = "github:numtide/flake-utils";
+    rust-overlay = {
+      url = "github:oxalica/rust-overlay";
+      inputs = {
+        nixpkgs.follows = "nixpkgs";
+        flake-utils.follows = "flake-utils";
+      };
+    };
+  };
+
+  outputs = { self, nixpkgs, rust-overlay, flake-utils, ... }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        pkgs = import nixpkgs {
+          inherit system;
+          overlays = [ (import rust-overlay) ];
+        };
+      in {
+        devShells.default = pkgs.mkShell rec {
+          rustToolchain = pkgs.rust-bin.stable.latest.default.override {
+            targets = [ "wasm32-unknown-unknown" ];
+            extensions = [ "rust-src" "rust-analyzer" ];
+          };
+          RUST_SRC_PATH = "${rustToolchain}/lib/rustlib/src/rust/library";
+
+          buildInputs = with pkgs; [ trunk rustToolchain cargo-watch ];
+        };
+      });
+}