diff --git a/backend/src/app.py b/backend/src/app.py
index e171851..2024da5 100644
--- a/backend/src/app.py
+++ b/backend/src/app.py
@@ -9,6 +9,8 @@ from .room import Room
 from .song import Song, init_db, get_song_by_title_artist, add_song_in_db
 from .song_fetch import lastfm_query_search, download_song_mp3
 
+from typing import Any
+
 dotenv.load_dotenv()
 
 
@@ -21,6 +23,18 @@ db_conn = get_connection()
 state = State(app, db_conn.cursor())
 init_db(state.db)
 
+state.rooms[1000] = Room(
+    id=1000,
+    coord=(1.0, 5.5),
+    name="Test Room",
+    pin=None,
+    tags=set(),
+    songs={},
+    history=[],
+    playing=[Song(uuid="<uuid>", title="<title>", artist="<artist>", tags=[], image_id="<img>", youtube_id="<yt>")],
+    playing_idx=0,
+)
+
 
 def error(msg: str, status: int = 400) -> Response:
     res = jsonify({"success": False, "error": msg})
@@ -28,6 +42,17 @@ def error(msg: str, status: int = 400) -> Response:
     return res
 
 
+def ws_broadcast(event: str, *, room_id: int | None = None, data: Any) -> None:
+    final = {}
+
+    if room_id is not None:
+        final["room_id"] = room_id
+
+    final["data"] = data
+
+    emit(event, final, broadcast=True, namespace="/")
+
+
 @app.get("/api/join")
 def join():
     room_id = request.args.get("room")
@@ -144,6 +169,8 @@ def add_song():
         ## add in DB
         add_song_in_db(info.artist, info.title, info.tags, info.img_id, yt_id)
 
+    ## HERE: add song in the room list
+
     return {"artist": info.artist, "title": info.title, "tags": info.tags, "image_id": info.img_id}
 
 
diff --git a/backend/src/room.py b/backend/src/room.py
index bee8b7f..8b67e4f 100644
--- a/backend/src/room.py
+++ b/backend/src/room.py
@@ -38,7 +38,8 @@ class Room:
     songs: dict[str, UserScoredSong]  # all songs + user score (the playlist)
     history: list[Song]  # all songs previously played
 
-    playing: list[Song]  # queue
+    ## playing queue info
+    playing: list[Song]
     playing_idx: int
 
     def renew_queue(self):
diff --git a/backend/src/song.py b/backend/src/song.py
index 39871cc..3507904 100644
--- a/backend/src/song.py
+++ b/backend/src/song.py
@@ -18,7 +18,7 @@ def init_db(db: Cursor):
     """)
 
 
-@dataclass(frozen=True)
+@dataclass(frozen=True, slots=True, kw_only=True)
 class Song:
     uuid: str
     title: str