Update faq.rst

**Proposed changes**:
Changed Gitter links to Rasa Community Forum links

**Status (please check what you already did)**:
- [x] made PR ready for code review
- [ ] added some tests for the functionality
- [x] updated the documentation
- [ ] updated the changelog

docs/faq.rst

@@ -42,7 +42,7 @@ Hence, the solution is to add more training samples. As this is only a warning,
 
 I have an issue, can you help me?
 ---------------------------------
-We'd love to help you. If you are unsure if your issue is related to your setup, you should state your problem in the `gitter chat <https://gitter.im/RasaHQ/rasa_nlu>`_.
+We'd love to help you. If you are unsure if your issue is related to your setup, you should state your problem in the `Rasa Community Forum <https://forum.rasa.com>`_.
 If you found an issue with the framework, please file a report on `github issues <https://github.com/RasaHQ/rasa_nlu/issues>`_
 including all the information needed to reproduce the problem.