Add debug output

src/de/steamwar/spectatesystem/PacketProcessor.java

@@ -67,6 +67,7 @@ class PacketProcessor {
         if(user == null)
             throw new IOException("Unknown user " + userId);
 
+        System.out.println("Player " + user.getUserName() + " joins!");
         Bukkit.getScheduler().runTask(SpectateSystem.get(), () -> new RPlayer(user.getUUID(), user.getUserName(), entityId));
     }