add a nix flake

flake.lock

@@ -0,0 +1,64 @@
+{
+  "nodes": {
+    "crane": {
+      "locked": {
+        "lastModified": 1769737823,
+        "narHash": "sha256-DrBaNpZ+sJ4stXm+0nBX7zqZT9t9P22zbk6m5YhQxS4=",
+        "owner": "ipetkov",
+        "repo": "crane",
+        "rev": "b2f45c3830aa96b7456a4c4bc327d04d7a43e1ba",
+        "type": "github"
+      },
+      "original": {
+        "owner": "ipetkov",
+        "repo": "crane",
+        "type": "github"
+      }
+    },
+    "flake-parts": {
+      "inputs": {
+        "nixpkgs-lib": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1769996383,
+        "narHash": "sha256-AnYjnFWgS49RlqX7LrC4uA+sCCDBj0Ry/WOJ5XWAsa0=",
+        "owner": "hercules-ci",
+        "repo": "flake-parts",
+        "rev": "57928607ea566b5db3ad13af0e57e921e6b12381",
+        "type": "github"
+      },
+      "original": {
+        "owner": "hercules-ci",
+        "repo": "flake-parts",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1769900590,
+        "narHash": "sha256-I7Lmgj3owOTBGuauy9FL6qdpeK2umDoe07lM4V+PnyA=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "41e216c0ca66c83b12ab7a98cc326b5db01db646",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-25.11",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "crane": "crane",
+        "flake-parts": "flake-parts",
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,102 @@
+{
+  description = "manages multiple identities (e.g. personal, work, university, ...) in git repos for you";
+
+  inputs = {
+    crane.url = "github:ipetkov/crane";
+
+    flake-parts = {
+      url = "github:hercules-ci/flake-parts";
+      inputs.nixpkgs-lib.follows = "nixpkgs";
+    };
+
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-25.11";
+  };
+
+  outputs = inputs @ { self, crane, ... }:
+    inputs.flake-parts.lib.mkFlake { inherit inputs; } ({ lib, ... }: {
+      systems = [ "x86_64-linux" "aarch64-linux" ];
+
+      perSystem = { pkgs, self', system, ... }: let
+        buildInputs = with pkgs; [
+          gpgme
+          pkg-config
+        ];
+
+        nativeBuildInputs = with pkgs; [
+          pkg-config
+        ];
+
+        crateSrc = lib.cleanSourceWith {
+          src = self.outPath;
+          filter = name: type: builtins.all (f: f name type) [
+            lib.sources.cleanSourceFilter
+            (name: type: !(builtins.elem (builtins.baseNameOf name) [ "flake.nix" "flake.lock" ]))
+          ];
+        };
+
+        craneArgs = {
+          src = crateSrc;
+          strictDeps = true;
+
+          inherit buildInputs nativeBuildInputs;
+        };
+
+        craneLib = crane.mkLib pkgs;
+
+        # Build the dependencies with different parameters
+        cargoArtifacts = craneLib.buildDepsOnly craneArgs;
+
+        cargoTOML = builtins.fromTOML (builtins.readFile ./Cargo.toml);
+      in {
+        packages.xtask = (craneLib.buildPackage ( craneArgs // {
+          inherit cargoArtifacts;
+
+          cargoExtraArgs = "--package xtask";
+
+          meta = {
+            licences = with lib.licences; [mit asl20];
+            platforms = [ system ];
+            mainProgram = "xtask";
+          };
+        }));
+
+        packages.default = (craneLib.buildPackage ( craneArgs // {
+          inherit cargoArtifacts;
+
+          nativeBuildInputs = craneArgs.nativeBuildInputs ++ [ self'.packages.xtask ];
+
+          postInstall = let
+            manDir = "$out/share/man/man1";
+          in ''
+            mkdir -p "${manDir}"
+            xtask manpage "${manDir}"
+            find "${manDir}" -type f -exec gzip {} \;
+          '';
+
+          meta = {
+            licences = with lib.licences; [mit asl20];
+            platforms = [ system ];
+            mainProgram = cargoTOML.package.name;
+          }
+          // lib.optionalAttrs (lib.attrsets.hasAttrByPath ["package" "description"] cargoTOML) {
+            inherit (cargoTOML.package) description;
+          };
+        }));
+
+        apps.default = {
+          type = "app";
+          program = let pkg = self'.packages.default; in "${pkg}/bin/${pkg.pname}";
+        };
+
+        devShells.default = craneLib.devShell {
+          checks = self'.checks;
+
+          inherit buildInputs nativeBuildInputs;
+
+          packages = with pkgs; [
+            # Cargo and rustc are provided by default.
+          ];
+        };
+      };
+    });
+}