Add a basic CONTRIBUTING.md

Provide basic instructions in-repository for contributing to Second
Life.

CONTRIBUTING.md

+# Contributor guidelines
+
+Thanks for your interest in contributing to Second Life! This document
+summarizes some of the most important points for people looking to contribute
+to the platform especially those looking to provide bug reports and code
+changes.
+
+## Table of contents
+
+- [Communication](#communication)
+- [Reporting bugs and requesting features](#reporting-bugs-and-requesting-features)
+- [Contributing pull requests](#contributing-pull-requests)
+
+## Communication
+
+Second Life has multiple channels for communication. Some of these channels are
+more end-user focused, while others are more tailored for
+developer-to-developer or support.
+
+- [feedback.secondlife.com][] is Second Life's primary community engagement
+  forum. Ideas and bug reports should be placed here unless they relate to
+  ongoing development issues and developer-to-developer communication.
+- [Public user groups][slug] are held on a regular basis, including those for
+  discussing open source development, content creation, server topics and more.
+- [Github issues][] provide a means for staff to organize their
+  work and collaborate with other developers. By default most user-facing
+  discussions should happen on [feedback.secondlife.com][] so that they are
+  visible to more people, can build consensus, and be placed onto our public
+  roadmap. Github issues are useful for collaboration between viewer forks
+  and the official upstream and when engineering-specific and technical
+  collaboration is beneficial. 
+- [Official forums][] exist for many topics including content creation,
+   scripting, social topics and more. 
+- The [opensource-dev mailing list][] is useful for announcements and
+  discussion between viewer maintainers. 
+
+
+## Reporting bugs and requesting features
+
+Report bugs and provide ideas for features using the respective board on Second
+Life's feedback portal:
+
+- [Features](https://feedback.secondlife.com/feature-requests)
+- [Scripting bugs](https://feedback.secondlife.com/scripting-bugs)
+- [Scripting features](https://feedback.secondlife.com/scripting-features)
+- [Server bugs](https://feedback.secondlife.com/scripting-bugs)
+- [Viewer bugs](https://feedback.secondlife.com/bug-reports)
+- [Web/Marketplace bugs](https://feedback.secondlife.com/web-bugs)
+- [Web/Marketplace features](https://feedback.secondlife.com/web-features)
+
+Creating posts on feedback.secondlife.com is important as it allows the greatest
+exposure and input from Second Life users. It also allows Linden Lab staff to
+place work on a single public roadmap.
+
+Issues created on feedback.secondlife.com are imported onto Github after they
+have been reviewed by staff and accepted. 
+
+## Contributing pull requests
+
+If you wish to contribute a new pull request, please ensure that:
+
+- You talk to other developers about how best to implement the work.
+- The functionality is desired. Be sure to talk to users and Second Life staff to ensure
+  the work is a good idea and will be accepted.
+- The work is high quality and the PR follows [PR etiquette][]
+- You have tested the work locally
+
+The [Git Style Guide](https://github.com/agis/git-style-guide) is also a good
+reference for best git practices.
+
+[feedback.secondlife.com]: https://feedback.secondlife.com
+[slug]: https://community.secondlife.com/blogs/entry/6509-introducing-the-second-life-public-calendar/
+[PR etiquette]: https://gist.github.com/mikepea/863f63d6e37281e329f8
+[Github issues]: https://github.com/secondlife/viewer/issues
+[Official forums]: https://community.secondlife.com/forums/
+[opensource-dev mailing list]: https://wiki.secondlife.com/wiki/OpenSource-Dev

README.md

@@ -35,9 +35,10 @@ Third party maintained forks, which include Linux compatible builds, are indexed
 ## Contribute
 
 Help make Second Life better! You can get involved with improvements by filing bugs, suggesting enhancements, submitting
-pull requests and more. See the [open source portal][] for details.
+pull requests and more. See the [CONTRIBUTING][] and the [open source portal][] for details.
 
 [Second Life]: https://secondlife.com/
 [download]: https://secondlife.com/support/downloads/
 [tpv]: http://wiki.secondlife.com/wiki/Third_Party_Viewer_Directory
 [open source portal]: http://wiki.secondlife.com/wiki/Open_Source_Portal
+[contributing]: https://github.com/secondlife/viewer/blob/main/CONTRIBUTING.md