Adding inital flake and gitignore

flake.nix

@@ -0,0 +1,43 @@
+{
+  description = "VSSM dev environment";
+
+  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+
+  outputs = { self, nixpkgs }:
+    let
+      systems = [ "x86_64-linux" "aarch64-linux" ];
+      forAllSystems = f:
+        nixpkgs.lib.genAttrs systems (system: f nixpkgs.legacyPackages.${system});
+    in
+    {
+      devShells = forAllSystems (pkgs: {
+        default = pkgs.mkShell.override { stdenv = pkgs.clangStdenv; } {
+          nativeBuildInputs = with pkgs; [
+            cmake
+            ninja
+            pkg-config
+            clang-tools   
+            gdb
+            valgrind
+          ];
+
+          buildInputs = with pkgs; [
+            boost
+            curl
+            libarchive
+            openssl
+            zlib
+            zstd
+            nlohmann_json
+            spdlog
+            cli11
+            # dotnet-runtime_8
+          ];
+
+          shellHook = ''
+            export CMAKE_EXPORT_COMPILE_COMMANDS=1
+          '';
+        };
+      });
+    };
+}