Add environment configuration for Nix

default.nix

@@ -0,0 +1,20 @@
+let
+  stable = import (fetchTarball { # 19.09
+    url = https://github.com/NixOS/nixpkgs-channels/archive/a22b0189002.tar.gz;
+    sha256 = "0rgd0cbxg9mrzb830hgjlvy134ivpfcnkyhbnlvvn8vl4y20zqmz";
+  }) {};
+in {
+  aeternityEnv = stable.stdenv.mkDerivation {
+    name = "ecrecover";
+    buildInputs = [
+      ## base
+      stable.stdenv
+      ## erlang
+      stable.erlangR21 # OTP 21.3.5.2
+      ## rust, required for building the NIF
+      stable.rustc
+      stable.cargo
+      stable.cmake
+    ];
+  };
+}