contributing.md: Add CONTRIBUTING.md

As discussed in the monthly OE4T meeting, move the contributing
guide into the master branch of meta-tegra.

This content includes the latest from the wiki page as of 2020-12-12

Signed-off-by: Dan Walkes <danwalkes@boulderai.com>

CONTRIBUTING.md

@@ -0,0 +1,42 @@
+Thank you for contributing to the OE4T project!  Your contributions are greatly appreciated!
+
+# Submitting Issues
+
+Use the Issues tab in [meta-tegra](https://github.com/OE4T/meta-tegra/issues) for issues specific to the meta-tegra layer.
+For general build issues or questions about getting started with your build setup please use the issues tab on [tegra-demo-distro](https://github.com/OE4T/tegra-demo-distro/issues).  For mender specific issues, use [OE4T's meta-mender-community](https://github.com/OE4T/meta-mender-community/issues) repo.
+
+When reporting build or runtime issues, please include as much information about your environment as you can. For example, the target
+hardware you are building for, branch/version information, etc.
+
+# Submitting Code Changes
+The OE4T project repositories follow the [OpenEmbedded Guidelines](https://www.openembedded.org/wiki/Commit_Patch_Message_Guidelines#Patch_Headers_and_Commit_Messages) so please review these when proposing your Pull Request.  A few highlights and additional requirements:
+* Please submit issues or pull requests through Github.
+* Only rebase and squash commits are used for PRs, so if you have a PR that is outstanding for a long time, please keep your
+  branch up to date by rebasing your changes, rather than merging.
+* Group commits based on their functionality and components changed.  For the first line, use something
+  like `component: Short Summary` to describe your change where `component` refers to a specific software
+  component being changed.
+* Please try to make incremental changes with multiple commits, rather than "big bang" single commits with changes spread across
+  multiple components.
+* Add a `Signed-off-by:` line to your commit, using `git commit -s` or a pre-commit hook like the one setup with [this script](https://github.com/OE4T/tegra-demo-distro/blob/master/scripts-setup/setup-git-hooks), using your real name and e-mail address
+(no anonymous contributions, please). This indicates that you have the right to submit the patch per the Developer's Certificate
+of Origin in the next section.
+
+## Developer's Certificate of Origin
+By making a contribution to this project, I certify that:
+1. 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
+2. 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
+3. The contribution was provided directly to me by some other person who certified (1), (2) or (3) and I have not modified it.
+4. 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.
+
+(Adapted from the [Linux kernel's certificate of origin](https://www.kernel.org/doc/html/latest/process/submitting-patches.html#developer-s-certificate-of-origin-1-1).)
+
+# Submitting Documentation Changes
+Wikis are enabled on the [meta-tegra](https://github.com/OE4T/meta-tegra) and [tegra-demo-distro](https://github.com/OE4T/tegra-demo-distro)
+repositories.  Please feel free to make appropriate changes to pages as needed, adding an edit message to describe your change.