Is there currently any way to vote on what music you play?
If voting is not relevant, and money is not an issue, you can set up a Spotify Collaborative Playlist.
It allows you to invite any Spotify user to edit your playlist.

Other than that, searching for "playlist voting app" returns a great amount of apps that do different versions of what you are looking for, but I haven't tried any of them.

https://outloud.dj/ seems particularly promising:


  At your next party, everybody controls the music.
  Mash your Spotify and iTunes playlists with those of your friends and build the ultimate playlist.
  Add any song through Spotify, even if you don't have an account.
  Project your playlist onto your TV with the push of a button.
  The app is free and no sign-ins and set-ups required.