Update CONTRIBUTING.md

CONTRIBUTING.md

@@ -250,5 +250,5 @@ If you are participating in the GitHub Externship, please read more about us and
 ## Community
 There are many ways to communicate with the community.
 
-1. The Palisadoes Foundation has a Slack channel where members can assist with support and clarification. Visit [slack.palisadoes.org](http://slack.palisadoes.org) to join our slack channel.
+1. The Palisadoes Foundation has a Slack channel where members can assist with support and clarification. Visit the [Talawa GitHub repository home page](https://github.com/PalisadoesFoundation/talawa) for the link to join our slack channel.
 1. We also have a technical email list run by [freelists.org](https://www.freelists.org/). Search for "palisadoes" and join. Members on this list are also periodically added to our marketing email list that focuses on less technical aspects of our work.