Add spotify queue

demo.py

@@ -140,6 +140,16 @@ class DemoController:
     def zidoo_seek(self, position_ms):
         self._film_ms = min(596000, int(position_ms))
 
+    def spotify_queue(self, key):
+        """What the demo's Spotify room plays next -- app.py's /api/spotify/queue."""
+        if not self._spotify.get(key):
+            raise ValueError("Only a Spotify stream one of your accounts is playing has a queue to show")
+        songs = ["Unknown Legend", "Old King", "Natural Beauty", "From Hank to Hendrix",
+                 "You and Me", "War of Man", "One of These Days", "Such a Woman",
+                 "Dreamin' Man", "Little Bit of Love", "Heart of Gold", "Old Man"]
+        return [{"song": song, "artist": "Neil Young", "image": None, "duration_ms": 240000}
+                for song in songs]
+
     def joined_keys(self):
         return [k for k in self.cfg.GUEST_ROOMS if k in self._joined]