Justin Bieber is still treating fans to #MusicMondays. Following 'PYD' with the King of R&B R Kelz, the teen sensation has released an up-beat Rodney Jerkins-produced track, 'Roller Coaster.' Taking the title literally, Bieber sings about the ups and downs of a relationship. 'Roller coaster, roller coaster/ One minute we were up, but the next we were falling down.'