Add Nix flake

.gitignore

@@ -1 +1,2 @@
 /target
+/result

flake.lock

@@ -0,0 +1,61 @@
+{
+  "nodes": {
+    "flake-utils": {
+      "inputs": {
+        "systems": "systems"
+      },
+      "locked": {
+        "lastModified": 1731533236,
+        "narHash": "sha256-l0KFg5HjrsfsO/JpG+r7fRrqm12kzFHyUHqHCVpMMbI=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "11707dc2f618dd54ca8739b309ec4fc024de578b",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1757487488,
+        "narHash": "sha256-zwE/e7CuPJUWKdvvTCB7iunV4E/+G0lKfv4kk/5Izdg=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "ab0f3607a6c7486ea22229b92ed2d355f1482ee0",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "nixpkgs": "nixpkgs"
+      }
+    },
+    "systems": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,36 @@
+{
+  description = "An intuitive system for organizing TODOs in code";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs = { self, nixpkgs, flake-utils }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        pkgs = nixpkgs.legacyPackages.${system};
+      in
+        {
+          packages.default = pkgs.rustPlatform.buildRustPackage {
+            name = "todos";
+            src = pkgs.lib.cleanSource ./.;
+            cargoLock.lockFile = ./Cargo.lock;
+
+            meta = with pkgs.lib; {
+              description = "An intuitive system for organizing TODOs in code";
+              homepage = "https://github.com/archtechx/todo-system";
+              license = licenses.mit;
+            };
+          };
+
+          devShells.default = pkgs.mkShell {
+            buildInputs = with pkgs; [
+              cargo
+              rustc
+              clippy
+            ];
+          };
+      }
+    );
+}