Add contributing help in the readme

diff --git a/README.md b/README.md
index 3d9894a7ed36bdea12d6d1a369b19182d4bfba47..9d744f5a395f58c203421e8c2a474f38fedb70b5 100644 (file)
--- a/README.md
+++ b/README.md
@@ -5,3 +5,15 @@ Nix derivation to install clever-tools - see https://github.com/CleverCloud/clev
 ## How to use it
 
 [See the example.nix](https://github.com/fretlink/clever-tools-nix/blob/master/example.nix)
+
+## How to publish a new version
+
+First, edit `clever-tools/default.nix`, to update the version number. For the expected hash, you can put `0000000000000000000000000000000000000000000000000000` (52 zeroes).
+
+Then, edit `default.nix`, update the `callPackage` line to the new version, as well as the `latest` value.
+
+Once you've done that, add a `mkOlderVersion` for the previous latest version. Once again, you can use the null hash for `sha256`.
+
+Then, run `nix build`. It will give you the correct values for the hashes. Correct those, run it again and you'll see `result-` directories, one per version. Go ahead and make sure they all work.
+
+Finally, don't forget to update `check.sh` with the latest version number.