Add Ruby 2.7 disclaimer

Author: 0x2c7

website/docs/guides/faq.md

@@ -3,6 +3,10 @@ id: FAQ
 slug: faq
 ---
 
+### Why does sometime Jard fail to stop in Ruby 2.7?
+
+Jard depends on Byebug. Byebug depends on Ruby Tracepoint. In Ruby 2.7.0 and 2.7.1, Tracepoint has a bug that breaks Byebug. The bug is fixed, and released in Ruby 2.7.2. See more at [this issue](https://github.com/deivid-rodriguez/byebug/issues/719).
+
 ### Can Ruby Jard work with Docker?
 
 Yes it does. However, if you are using `docker-compose up`, you may change your workflow a little bit. That command is not meant to be interactive. To enable Ruby Jard in docker: