add nix flake

flake.lock

@@ -0,0 +1,27 @@
+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1771848320,
+        "narHash": "sha256-0MAd+0mun3K/Ns8JATeHT1sX28faLII5hVLq0L3BdZU=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "2fc6539b481e1d2569f25f8799236694180c0993",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,30 @@
+{
+  description = "Static site generator in c++";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+  };
+
+  outputs =
+    {
+      self,
+      nixpkgs,
+    }:
+
+    {
+      devShells = {
+        default = nixpkgs.mkShell {
+          packages = with nixpkgs; [
+            gcc
+            gnumake
+
+            md4c
+            catch2_3
+
+            clang-tools
+            gdb
+          ];
+        };
+      };
+    };
+}