Merge pull request #3360 from kenhys/guide-to-discuss

Navigate to community forum instead of mailing list

CONTRIBUTING.md

@@ -6,7 +6,7 @@ We'd love your contribution. Here are the guidelines!
 
 RESOURCES of [Official site](https://www.fluentd.org/) and [Fluentd documentation](https://docs.fluentd.org/) may help you.
 
-If you have further questions about Fluentd and plugins, please direct these to [Mailing List](https://groups.google.com/forum/#!forum/fluentd).
+If you have further questions about Fluentd and plugins, please direct these to [Community Forum](https://discuss.fluentd.org/).
 Don't use Github issue for asking questions. Here are examples:
 
 - I installed xxx plugin but it doesn't work. Why?
@@ -16,7 +16,7 @@ Don't use Github issue for asking questions. Here are examples:
 We may close such questions to keep clear repository for developers and users.
 Github issue is mainly for submitting a bug report or feature request. See below.
 
-If you can't judge your case is a bug or not, use mailing list or slack first.
+If you can't judge your case is a bug or not, use community forum or slack first.
 
 ## Found a bug?
 

README.md

@@ -77,7 +77,7 @@ You can run specified test via `TEST` environment variable:
 - Website: https://www.fluentd.org/
 - Documentation: https://docs.fluentd.org/
 - Project repository: https://github.com/fluent
-- Discussion: https://groups.google.com/group/fluentd
+- Discussion: https://discuss.fluentd.org/
 - Slack / Community: https://slack.fluentd.org
 - Newsletters: https://www.fluentd.org/newsletter
 - Author: [Sadayuki Furuhashi](https://github.com/frsyuki)