add FAQ about offline mode (#325)

* add FAQ about offline mode

* reword slightly to address review

Author: Chew

docs/general/faq.md

@@ -212,6 +212,18 @@ If an achievement doesn't work correctly for you, there is a very good chance it
 
 If the game has tickets, click on the 'open tickets' link. There will be a list to show any reports of broken achievements. You can comment on these to add helpful details or say you have a problem with this achievement too.
 
+### Can I earn achievements offline?
+
+We don't currently support a fully offline mode. You must be connected to the internet when you start a playing session.
+
+If you lose connection while playing, you must ensure your emulator stays open until you re-connect.
+Once you do, your achievements will be synced.
+
+If you close your emulator before your achievements save, you must submit a [manual unlock](#how-do-i-request-a-manual-unlock).
+If you have a screenshot or recording of you earning the achievement, this is usually sufficient evidence, so be sure
+to take a screenshot of your achievements if you notice you are offline and are unable to reconnect.
+Please do not make a ticket if you earned the achievement, follow the manual unlock process.
+
 ---
 
 ## Account FAQ