doc: Add 'how to contribute' section

Document how to contribute to the project. Highlight the fact, that
it expected that the PRs are also following the Linux community
contributions guidelines (clean series).

Signed-off-by: Daniel Wagner <dwagner@suse.de>

diff --git a/README.md b/README.md
index 20623c1ca612ef01f8b30ab75918ee648ceeca99..837f8600657891fb3ab3ac7b7e263bc191bcf172 100644 (file)
--- a/README.md
+++ b/README.md
@@ -263,3 +263,49 @@ introduced in the Linux kernel release v4.15. Hence nvme-cli 2.x is
 only working on kernels >= v4.15. For older kernels nvme-cli 1.x is
 recommended to be used.
 
+## How to contribute
+
+There are two ways to send code changes to the project. The first one
+is by sending the changes to linux-nvme@lists.infradead.org. The
+second one is by posting a pull request on github. In both cases
+please follow the Linux contributions guidelines as documented in
+
+https://docs.kernel.org/process/submitting-patches.html#
+
+That means the changes should be a clean series (no merges should be
+present in a github PR for example) and every commit should build.
+
+See also https://opensource.com/article/19/7/create-pull-request-github
+
+### How to cleanup your series before creating PR
+
+This example here assumes, the changes are in a branch called
+fix-something, which branched away from master in the past. In the
+meantime the upstream project has changed, hence the fix-something
+branch is not based on the current HEAD. Before posting the PR, the
+branch should be rebased on the current HEAD and retest everything.
+
+For example rebasing can be done by following steps
+
+```shell
+# Update master branch
+#   upstream == https://github.com/linux-nvme/nvme-cli.git
+$ git switch master
+$ git fetch --all
+$ git reset --hard upstream/master
+
+# Make sure all dependencies are up to date and make a sanity build
+$ meson subprojects update
+$ ninja -C .build
+
+# Go back to the fix-something branch
+$ git switch fix-something
+
+# Rebase it to the current HEAD
+$ git rebase master
+[fixup all merge conflicts]
+[retest]
+
+# Push your changes to github and trigger a PR
+$ git push -u origin fix-something
+```