Add contribution guidelines (#62)

.github/CONTRIBUTING.md

@@ -0,0 +1,47 @@
+# How To Contribute
+
+Thank you for considering contributing to `rpsl-rs`!
+This document intends to make contribution more accessible while aligning expectations.
+Please don't hesitate to open issues and PRs regardless if anything is unclear.
+
+By contributing to `rpsl-rs`, you agree that your code will be licensed under the terms of the MIT License without any additional terms or conditions.
+
+## Getting Started
+
+To gain an overview of `rpsl-rs`, please read the [documentation](https://docs.rs/rpsl-rs).
+
+## General Guidelines
+
+- Contributions of all sizes are welcome, including single line grammar / typo fixes.
+- For new features, documentation and tests are a requirement.
+- Changes must pass CI. PRs with failing CI will be treated as drafts unless you explicitly ask for help.
+- Simplicity is a core objective of `rpsl-rs`. Please open an issue before working on a new feature to discuss it.
+
+## Development Environment
+
+### Devcontainer
+
+For users of IDEs with support for devcontainers, it's usage is recommended.
+
+### Other
+
+Ensure a recent version of rustup is available, otherwise [install it](https://www.rust-lang.org/tools/install).
+
+## Coding Standards
+
+`rpsl-rs` uses [`rustfmt`](https://github.com/rust-lang/rustfmt) for uniform fomatting and [`clippy`](https://github.com/rust-lang/rust-clippy) for basic linting and enforcement of best practices. Please run both before submitting a PR to avoid being reprimanded by CI.
+
+```sh
+$ cargo fmt --all --check
+$ cargo clippy --all-targets --all-features
+```
+
+In addition to basic formatting and linting, a high code coverage should be maintained. Property based tests are used to ensure the parser can deal with any kind of RPSL input. All tests need to pass before a PR can be merged.
+
+```sh
+$ cargo test
+```
+
+## Performance
+
+To ensure that the parser stays performant, benchmarks are run on every PR. To execute them locally, run `cargo bench`.

README.md

@@ -159,6 +159,11 @@ Ref:            https://rdap.arin.net/registry/entity/THEFA-3
 
 To extract each individual object, the [parse_whois_response] function can be used to parse the response into a `Vec` containing all individual [ObjectView]s within the response. Examples can be found in the function documentation.
 
+## Contributing
+
+Contributions of all sizes that improve `rpsl-rs` in any way, be it DX/UX, documentation, performance or other are highly appreciated.
+To get started, please read the [contribution guidelines](.github/CONTRIBUTING.md). Before starting work on a new feature you would like to contribute that may impact simplicity, reliability or performance, please open an issue first.
+
 [RFC 2622]: https://datatracker.ietf.org/doc/html/rfc2622
 [Object]: https://docs.rs/rpsl-rs/latest/rpsl/struct.Object.html
 [ObjectView]: https://docs.rs/rpsl-rs/latest/rpsl/struct.ObjectView.html