Add a little explication on dev mode in README
Add a little explication on dev mode in README

Chocobozzz/PeerTube,Green-Star/PeerTube,Green-Star/PeerTube,Chocobozzz/PeerTube,Green-Star/PeerTube,Chocobozzz/PeerTube,Chocobozzz/PeerTube,Green-Star/PeerTube