onix: add onix project structure

Author: leojrfs

default.nix

@@ -0,0 +1,15 @@
+let
+  onix = import (builtins.fetchGit {
+    url = "https://github.com/rizo/onix.git";
+    rev = "1a67fe51d4d1676f38088e635a00dfdae5bae70b";
+  }) { verbosity = "info"; };
+
+in onix.env {
+  path = ./.;
+  vars = {
+    "with-test" = true;
+    "with-doc" = true;
+    "with-dev-setup" = true;
+  };
+  deps = { "ocaml-base-compiler" = "5.1.0"; };
+}