add flake.nix

flake.nix

@@ -0,0 +1,23 @@
+{
+  description = "git repos";
+
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
+  };
+
+  outputs = {
+    self,
+    nixpkgs,
+  }: let
+    inherit (nixpkgs.lib) genAttrs makeBinPath;
+    eachSystem = fn:
+      genAttrs [ "x86_64-linux" ]
+      (system: fn nixpkgs.legacyPackages.${system});
+  in {
+    devShells = eachSystem (_: pkgs: {
+      default = pkgs.mkShell {
+        buildInputs = with pkgs; [nim openssl];
+      };
+    });
+  };
+}