move FAQ into separate file, add links

docs/gitbook/SUMMARY.md

@@ -2,6 +2,7 @@
 
 * [Introduction](README.md)
 * [How it works](how-it-works.md)
+* [Frequently asked questions](faq.md)
 
 ## Install
 

docs/gitbook/faq.md

@@ -0,0 +1,21 @@
+# Frequently asked questions
+
+**Can Flagger be part of my integration tests?**
+> Yes, Flagger supports webhooks to do integration testing.
+
+**What if I only want to target beta testers?**
+> That's a feature in Flagger, not in App Mesh. It's on the App Mesh roadmap.
+
+**When do I use A/B testing when Canary?**
+> One advantage of using A/B testing is that each version remains separated and routes aren't mixed.
+>
+> Using a Canary deployment can lead to behaviour like this one observed by a
+> user:
+>
+> [..] during a canary deployment of our nodejs app, the version that is being served <50% traffic reports mime type mismatch errors in the browser (js as "text/html")
+> When the deployment Passes/ Fails (doesn't really matter) the version that stays alive works as expected. If anyone has any tips or direction I would greatly appreciate it. Even if its as simple as I'm looking in the wrong place. Thanks in advance!
+>
+> The issue was that we were not maintaining session affinity while serving files for our frontend. Which resulted in any redirects or refreshes occasionally returning a mismatched app.*.js file (generated from vue)
+>
+> Read up on [A/B testing](https://docs.flagger.app/usage/ab-testing).
+