README: description, contributing

Set up the usual project rules, following what wayland-protocols and
wayland use.

Granting permissions is eased given this is mostly for documentation.
Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>

README.md

-# color-and-hdr
+# Color management and HDR documentation for FOSS graphics
+
+Documentation in [this repository](https://gitlab.freedesktop.org/pq/color-and-hdr)
+is intended to help with the design and implementation of color
+management and HDR support on FOSS graphincs stacks, including
+Mesa (EGL, Vulkan WSI), Linux (DRM KMS), Wayland (compositors and
+applications), and even X11.
+
+This is not an archive of proprietary documents like SMPTE, ITU, or VESA
+specifications. All content must follow the [license](LICENSE).
+
+## History
+
+Originally this documentation was started to better explain how
+[Wayland color management extension](https://gitlab.freedesktop.org/wayland/wayland-protocols/-/merge_requests/14)
+should be used and what it means.
+
+Widening community interestests particularly in HDR prompted for moving
+the documentation into this separate repository to allow a more
+streamlined way of contributing to it.
+
+For now, this project lives in a personal space, but if it gets more
+traction, moving it into an independent Gitlab group is possible without
+losing any Issues or MRs.
+
+## Releases
+
+No releases are made from this repository. Use date or the git hash to
+refer to specific revisions of the contents.
+
+## Contributing
+
+Open Issues and Merge Requests in Gitlab as usual. Use your own forked
+repository for MR branches (@pq is exempt as long as this repository is
+hosted in his personal Gitlab group). Each commit must carry
+Signed-off-by tag to denote that the submitter adheres to
+[Developer Certificate of Origin 1.1](https://developercertificate.org/).
+
+All merge requests need to be accepted by at least one other person with
+Developer or higher access level.
+
+Reporter level access can be given by invite without any particular
+requirements.
+
+Developer access can be given on request, provided the person is
+actively participating in discussions and has contributed an accepted
+MR.
+
+Maintainer access is given on Maintainers' collective discretion.
+
+## Conduct
+
+This project follows
+[the freedesktop.org Contributor Covenant](https://www.freedesktop.org/wiki/CodeOfConduct).
 
-Color management and HDR documentation for FOSS graphics
\ No newline at end of file