Show matched Matrix contacts from device addressbook to user
Telegram, Viber and other modern messengers checks device addressbook and shows to user all matched contacts, that have real accounts in current messenger. This is very useful feature, because users immediately after installing new app can see, that many of his friends already use this messenger, and can start talking with them.
So will be good to implement this in Pattle: after first login in app - ask permission to device addressbook and show all matched contacts for user.