Add CONTRIBUTING.md

closes https://github.com/official-stockfish/Stockfish/pull/4741

No functional change

.github/CONTRIBUTING.md

@@ -0,0 +1,85 @@
+# Contributing to Stockfish
+
+Welcome to the Stockfish project! We are excited that you are interested in
+contributing. This document outlines the guidelines and steps to follow when
+making contributions to Stockfish.
+
+## Table of Contents
+
+- [Building Stockfish](#building-stockfish)
+- [Making Contributions](#making-contributions)
+  - [Reporting Issues](#reporting-issues)
+  - [Submitting Pull Requests](#submitting-pull-requests)
+- [Code Style](#code-style)
+- [Community and Communication](#community-and-communication)
+- [License](#license)
+
+## Building Stockfish
+
+In case you do not have a C++ compiler installed, you can follow the
+instructions from our wiki.
+
+- [Linux][linux-compiling-link]
+- [Windows][windows-compiling-link]
+- [macOS][macos-compiling-link]
+
+## Making Contributions
+
+### Reporting Issues
+
+If you find a bug, please open an issue on the
+[issue tracker][issue-tracker-link]. Be sure to include relevant information
+like your operating system, build environment, and a detailed description of the
+problem.
+
+_Please note that Stockfish's development is not focused on adding new features.
+Thus any issue regarding missing features will potentially be closed without
+further discussion._
+
+### Submitting Pull Requests
+
+- Functional changes need to be tested on fishtest. See
+  [Creating my First Test][creating-my-first-test] for more details.
+  The accompanying pull request should include a link to the test results and
+  the new bench.
+
+- Non-functional changes (e.g. refactoring, code style, documentation) do not
+  need to be tested on fishtest, unless they might impact performance.
+
+- Provide a clear and concise description of the changes in the pull request
+  description.
+
+_First time contributors should add their name to [AUTHORS](../AUTHORS)._
+
+_Stockfish's development is not focused on adding new features. Thus any pull
+request introducing new features will potentially be closed without further
+discussion._
+
+## Code Style
+
+We do not have a strict code style. But it is best to stick to the existing
+style of the file you are editing.
+
+## Community and Communication
+
+- Join the [Stockfish discord][discord-link] to discuss ideas, issues, and
+  development.
+- Participate in the [Stockfish GitHub discussions][discussions-link] for
+  broader conversations.
+
+## License
+
+By contributing to Stockfish, you agree that your contributions will be licensed
+under the GNU General Public License v3.0. See [Copying.txt][copying-link] for
+more details.
+
+Thank you for contributing to Stockfish and helping us make it even better!
+
+[copying-link]: https://github.com/official-stockfish/Stockfish/blob/master/Copying.txt
+[discord-link]: https://discord.gg/GWDRS3kU6R
+[discussions-link]: https://github.com/official-stockfish/Stockfish/discussions/new
+[creating-my-first-test]: https://github.com/glinscott/fishtest/wiki/Creating-my-first-test#create-your-test
+[issue-tracker-link]: https://github.com/official-stockfish/Stockfish/issues
+[linux-compiling-link]: https://github.com/official-stockfish/Stockfish/wiki/Compiling-from-source#linux
+[windows-compiling-link]: https://github.com/official-stockfish/Stockfish/wiki/Compiling-from-source#windows
+[macos-compiling-link]: https://github.com/official-stockfish/Stockfish/wiki/Compiling-from-source#macos

README.md

@@ -92,6 +92,8 @@ Detailed compilation instructions for all platforms can be found in our
 
 ## Contributing
 
+__See [Contributing Guide](./.github/CONTRIBUTING.md).__
+
 ### Donating hardware
 
 Improving Stockfish requires a massive amount of testing. You can donate your