docs: Extend CONTRIBUTING about maintenance, discussions, issues, pul…

…l requests etc.

Signed-off-by: robot9001 <[email protected]>

CONTRIBUTING.md

@@ -1,14 +1,123 @@
-CONTRIBUTING
-============
+# CONTRIBUTING
 
-License
--------
+Thank you for contributing to the `rust-magic` project, which contains the `magic` Rust crate!
 
-This project is dual-licensed under the MIT and the Apache-2.0 licenses, see [LICENSE.md](LICENSE.md).
+## Maintenance
 
-Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.
+Please note that the project is only maintained passively by @robo9k \
+This is sometimes also called ["casual maintenance intended"](https://casuallymaintained.tech/).
 
-Security
---------
+This means that it might take longer for the maintainers to look at your contributions, e.g.
+pull requests that require much code review might not be merged
+and issues that require much research/work might remain unresolved.
 
-For security related contributions, please follow the policy in [SECURITY.md](SECURITY.md).
+That being said, the project welcomes your contributions and will try to
+prioritize security issues (see [Security](#Security))
+and bug reports.
+
+## Discussions
+
+Please use [discussions](https://github.com/robo9k/rust-magic/discussions) to ask and answer questions.
+
+The maintainers will try and answer questions, but you can answer other users' questions, too.
+
+## Issues
+
+Please use issues to [create bug reports](https://github.com/robo9k/rust-magic/issues/new?assignees=&labels=bug&projects=&template=bug-report.md&title=),
+[suggest features](https://github.com/robo9k/rust-magic/issues/new?assignees=&labels=enhancement&projects=&template=feature-request.md&title=) or
+[submit a custom issue](https://github.com/robo9k/rust-magic/issues/new?assignees=&labels=enhancement&projects=&template=feature-request.md&title=).\
+The issue templates will guide you towards the expected format.
+
+Please take a look at [existing issues](https://github.com/robo9k/rust-magic/issues) before
+creating new ones.
+
+## Pull requests
+
+Please use [pull requests](https://github.com/robo9k/rust-magic/pulls) to propose concrete changes. Before doing so,
+use discussions or issues to align your implementation ideas with the project maintainers.
+
+## Code
+
+The project is pretty standard for Rust and GitHub.
+It uses `cargo`, `crates.io`, GitHub Actions and GitHub Pages.
+
+Check the [crate README](https://github.com/robo9k/rust-magic/blob/main/README-crate.md) for
+the Minimum Supported Rust Version and
+requirements of the `magic-sys` crate / the `libmagic` C library.
+
+When developing code, please use `cargo clippy` and `cargo fmt`.
+
+New code should also come with new documentation (`cargo doc`, readme) and tests (`cargo test`, GitHub Actions).\
+Changed code should accordingly result in changed documentation and tests.\
+There are no hard rules on good tests, test coverage or what makes good documentation,
+but try to adhere to the [Rust API Guidelines](https://rust-lang.github.io/api-guidelines/documentation.html).
+If you are unsure, just ask.
+
+## Commits
+
+Commit messages should follow [Conventional Commits](https://www.conventionalcommits.org/en/v1.0.0/) and
+use the additional types `build:`, `chore:`, `ci:`, `docs:`, `style:`, `refactor:`, `perf:`, `test:`.\
+Ideally use breaking change messages according to [Semantic Versioning](https://semver.org/).\
+You to not have to provide a changelog entry
+(we use the [keep a changelog](https://keepachangelog.com/en/1.1.0/) format)
+but it helps if you provide a short summary in your pull request.
+
+Also see [Signoff](#Signoff) as part of the DCO.
+
+There are other conventions/rules, but the general idea is that continous integration will run for your
+pull request and fail if something is not in order (`cargo deny`, linear Git history to name a few).\
+Don't worry trying to get something perfect on the first try - you can always ask the maintainers for
+help and force-push fixes to your pull request branch. We're no wizards 🧙
+
+## Donations
+
+The project does _not_ accept donations, monetary or otherwise.
+
+## License
+
+This project is dual-licensed under the MIT and the Apache-2.0 licenses, see [LICENSE](LICENSE.md).
+
+Unless you explicitly state otherwise,
+any contribution intentionally submitted for inclusion in the work by you,
+as defined in the Apache-2.0 license,
+shall be dual licensed as above, without any additional terms or conditions.
+
+Also see the [GitHub Terms of Service](https://docs.github.com/en/site-policy/github-terms/github-terms-of-service#6-contributions-under-repository-license).
+
+## Developer Certificate of Origin
+
+As per https://developercertificate.org/ Version 1.1:
+
+```
+By making a contribution to this project, I certify that:
+
+(a) The contribution was created in whole or in part by me and I
+    have the right to submit it under the open source license
+    indicated in the file; or
+
+(b) The contribution is based upon previous work that, to the best
+    of my knowledge, is covered under an appropriate open source
+    license and I have the right under that license to submit that
+    work with modifications, whether created in whole or in part
+    by me, under the same open source license (unless I am
+    permitted to submit under a different license), as indicated
+    in the file; or
+
+(c) The contribution was provided directly to me by some other
+    person who certified (a), (b) or (c) and I have not modified
+    it.
+
+(d) I understand and agree that this project and the contribution
+    are public and that a record of the contribution (including all
+    personal information I submit with it, including my sign-off) is
+    maintained indefinitely and may be redistributed consistent with
+    this project or the open source license(s) involved.
+```
+
+### Signoff
+
+Please use [`git commit --signoff`](https://git-scm.com/docs/git-commit#Documentation/git-commit.txt---signoff).
+
+## Security
+
+For security related contributions, please follow the policy in [SECURITY](SECURITY.md).