Merge pull request #3625 from the-turing-way/aleesteele-patch-3

Update slack-welcome-guide.md

book/website/community-handbook/communication-channels/slack-welcome-guide.md

@@ -2,6 +2,8 @@
 
 # Welcome to *The Turing Way* Slack!
 
+**Not a member of our Slack workspace? You can join using the following link: [https://tinyurl.com/jointuringwayslack](https://tinyurl.com/jointuringwayslack)**
+
 Slack is one of our core communication channels within the *The Turing Way* community. It is a space where folks ask questions, learn about each other's work, and get involved with *The Turing Way* and other projects. While it is not the *only* communication channel used by the community, it is a popular platform, increasingly used by remote teams around the world.
 
 *Here is a short guide to the default slack channels (meaning, you've already been added to them when you joined this space!)*: