Assign custom ringtone to contacts

I updated my phone to Nougat by sideloading the update. Everythings fine except for one small problem.

I'm unable to assign ringtones from my playlists to contacts. I used to do this till MM. Now there is no option to search outside of the built-in tones. I could assign one song as the default ringtone, but not to individual contacts.

Any help here.