Add Contribute section to readme.md

Author: wooorm

readme.md

@@ -161,6 +161,13 @@ For example, the following node:
 <i class="foo">bar</i>
 ```
 
+## Contribute
+
+See [`contribute.md` in `remarkjs/remarkj`][contribute] for ways to get started.
+
+This organisation has a [Code of Conduct][coc].  By interacting with this
+repository, organisation, or community you agree to abide by its terms.
+
 ## License
 
 [MIT][license] © [Titus Wormer][author]
@@ -210,3 +217,7 @@ For example, the following node:
 [rehype]: https://github.com/rehypejs/rehype
 
 [hast]: https://github.com/syntax-tree/hast
+
+[contribute]: https://github.com/remarkjs/remark/blob/master/contributing.md
+
+[coc]: https://github.com/remarkjs/remark/blob/master/code-of-conduct.md