message: use joined_rooms rather than sync to reduce load
diff: @@ -33,10 +33,9 @@ def get_users(homeserver, room_id, token, user_prefix, name_suffix):
  return { uid: joined.get(uid).get("display_name") for uid in user_ids }
  def get_rooms(homeserver, token):
  - res = requests.get(homeserver + "/_matrix/client/r0/sync?access_token=" + token).json()
  + res = requests.get(homeserver + "/_matrix/client/r0/joined_rooms?access_token=" + token).json()
  room_ids = []
  - for room_id in res["rooms"]["join"]:
  - room = res["rooms"]["join"][room_id]
  + for room_id in res["joined_rooms"]:
  room_ids.append(room_id)
  return room_ids
  