Spotify allows you to create playlists together with other people (your friends) - spotify.com 
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Learn how to make collaborative playlists with Spotify on iPhone. Team up with your friends and music comrades to create and edit the ultimate playlist -
spotify.com
Let others add, delete, and reorder tracks on a playlist you’ve created by making it collaborative: 1. Tap Your Library. 2. Tap Playlists and select one. 3. Tap '...' in the top-right corner. 4. Tap Make Collaborative. 5. Share it with your friends!
Anyone that follows the playlist is able to collaborate on it.