feat: add nix docs

CHANGELOG.md

@@ -11,6 +11,15 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+- documentation about nix packages
+
+### Thanks
+
+Thank you to [@Sekky61](https://github.com/Sekky61) for the information
+on Issue [#280](https://github.com/lucassabreu/clockify-cli/pull/280).
+
 ## [v0.56.2] - 2025-09-30
 
 ### Fixed

README.md

@@ -72,6 +72,34 @@ The installed application for a default `go` installation should be located on y
 
 [go-envs]: https://pkg.go.dev/cmd/go#hdr-Environment_variables
 
+#### Using `nix`/[NUR](http://github.com/nix-community/NUR)
+
+Add this input, overlay and package into your flake:
+
+```nix
+# ...
+
+  inputs = {
+    nur = {
+      url = "github:nix-community/NUR";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+  };
+
+# ...
+
+  pkgs = import nixpkgs {
+    inherit system;
+    overlays = [ nur.overlays.default ];
+  };
+
+# ...
+
+  environment.systemPackages = with pkgs; [
+    nur.repos.lucassabreu.clockify-cli
+  ];
+```
+
 #### By Hand
 
 Go to the [releases page](https://github.com/lucassabreu/clockify-cli/releases) and download the pre-compiled