:handshake: Add the official django discord community link. (#174)

* Add discord link

* Update README.md

Updates description to match Django Project's and fixes lint error.

Co-authored-by: Jeff Triplett <jefftriplett@users.noreply.github.com>

README.md

@@ -315,6 +315,7 @@ _A short list of Python packages that work well with Django._
 - [Django Users Google Group](https://groups.google.com/forum/#!forum/django-users/) - Very active discussion board for questions/answers.
 - [Developers Google Group](https://groups.google.com/forum/#!forum/django-developers/) - For contributions to Django itself only.
 - [Twitter](https://twitter.com/djangoproject/) - For official announcements on updates, security fixes, etc.
+- [Discord Server](https://discord.com/invite/xcRH6mN4fa) - Django Discord Community.
 - IRC Channel - Chat with other Django users at irc://irc.freenode.net/django.
 <!--lint enable double-link-->