CONTRIBUTING.md in reveal-ck-3.7.0

- old
+ new

@@ -15,5 +15,9 @@
 - Should follow the coding style of the file you work in, most importantly:
   - Tabs to indent
   - Single-quoted strings
 - Should be made towards the **dev branch**
 - Should be submitted from a feature/topic branch (not your master)
+
+
+### Plugins
+Please do not submit plugins as pull requests. They should be maintained in their own separate repository. More information here: https://github.com/hakimel/reveal.js/wiki/Plugin-Guidelines