add flake.nix (#1)

example taken from github:jnsahaj/lumen

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": 1736701207,
+        "narHash": "sha256-jG/+MvjVY7SlTakzZ2fJ5dC3V1PrKKrUEOEE30jrOKA=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "ed4a395ea001367c1f13d34b1e01aa10290f67d6",
+        "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 +1,41 @@
+{
+  description = "Packard is a simple RSS aggregator meant to allow you to take a quick glance at what's occurring in topics you care about.";
+
+  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 = import nixpkgs {inherit system;};
+    in {
+      packages = {
+        packard = let
+          manifest = (pkgs.lib.importTOML ./Cargo.toml).package;
+        in
+          pkgs.rustPlatform.buildRustPackage {
+            pname = manifest.name;
+            version = manifest.version;
+
+            cargoLock.lockFile = ./Cargo.lock;
+
+            src = pkgs.lib.cleanSource ./.;
+
+            nativeBuildInputs = [pkgs.pkg-config];
+            buildInputs = [pkgs.openssl];
+          };
+        default = self.packages.${system}.packard;
+      };
+    })
+    // {
+      overlays.default = final: prev: {
+        inherit (self.packages.${final.system}) packard;
+      };
+    };
+}