Redirect discussions to discourse (#122)

* Redirect to discourse

Signed-off-by: Aaron Chong <aaronchongth@gmail.com>

* Update README.md

Co-authored-by: Grey <mxgrey@intrinsic.ai>
Signed-off-by: Aaron Chong <aaronchongth@gmail.com>

---------

Signed-off-by: Aaron Chong <aaronchongth@gmail.com>
Co-authored-by: Grey <mxgrey@intrinsic.ai>

Author: aaronchongth

README.md

@@ -15,7 +15,7 @@ More about RMF, including build instructions, can be found [here](https://github
 
 If you need support on RMF (e.g. bug reports, feature requests), you can find our support guidelines [here](https://openrmf.readthedocs.io/en/latest/support/index.html).
 
-For general questions about RMF, you are encouraged to visit the [discussion board](https://github.com/open-rmf/rmf/discussions).
+For general questions about RMF, you are encouraged to visit the [open-rmf discourse](https://discourse.openrobotics.org/c/open-rmf/open-rmf-general/103).
 
 ## Contributing
 Guidelines on contributing to `rmf_traffic` can be found [here](CONTRIBUTING.md).