Feature: Listen button

[OlegKunitsyn]

For now all users that can join the audio stream are admins. I've extended userController by

    const role = users.length === 0 ? 'admin' : 'visitor'
    const user = {id,name,room,role};
...
    const role = usersInVoice.length === 0 ? 'admin' : 'visitor'
    const user = {id,name,room,role};

and replaced user:admin with user:user.role. In result, we have two roles of users.
Furthermore, visitors may get Listen button instead of admn's Join voice

[dumbbellcode]

Hey @OlegKunitsyn, you may open up a pull request, let me review it.
Having a mute button is a good idea, will work on it.

[sinahosseini76]

Hey @OlegKunitsyn I agree with you,
The Mute button is a good idea will all visitor can talk or not and handle echo sound of visitors with mute button!

[sinahosseini76]

Could you please add this mute button ? @OlegKunitsyn @Sudheer121