add flake

.envrc

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

.gitignore

@@ -1,3 +1,5 @@
 /target
 Cargo.lock
 data
+.direnv
+result

flake.lock

@@ -0,0 +1,42 @@
+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1670276674,
+        "narHash": "sha256-FqZ7b2RpoHQ/jlG6JPcCNmG/DoUPCIvyaropUDFhF3Q=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "52e3e80afff4b16ccb7c52e9f0f5220552f03d04",
+        "type": "github"
+      },
+      "original": {
+        "id": "nixpkgs",
+        "ref": "release-22.11",
+        "type": "indirect"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs",
+        "utils": "utils"
+      }
+    },
+    "utils": {
+      "locked": {
+        "lastModified": 1667395993,
+        "narHash": "sha256-nuEHfE/LcWyuSWnS8t12N1wc105Qtau+/OdUAjtQ0rA=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "5aed5285a952e0b949eb3ba02c12fa4fcfef535f",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,22 @@
+{
+  inputs = {
+    utils.url = "github:numtide/flake-utils";
+    nixpkgs.url = "nixpkgs/release-22.11";
+  };
+
+  outputs = {
+    self,
+    nixpkgs,
+    utils,
+  }:
+    utils.lib.eachDefaultSystem (system: let
+      pkgs = (import nixpkgs) {
+        inherit system;
+      };
+    in rec {
+      # `nix develop`
+      devShell = pkgs.mkShell {
+        nativeBuildInputs = with pkgs; [rustc cargo bacon cargo-edit cargo-outdated clippy cargo-audit cargo-msrv];
+      };
+    });
+}