Do Monks add their modifier damage to flurry of blows?

@mikemearls Do Monks add their modifier damage to the bonus action flurry of blows or martial arts damage rolls?

— King Wizard (@_Matafer) January 21, 2016

Yes, they do add it. https://t.co/81pphBoEUS

— Mike Mearls (@mikemearls) January 21, 2016

@mikemearls @_Matafer but which?

— P. Cole (@UCFH) January 21, 2016

@_Matafer @UCFH yup, both

— Mike Mearls (@mikemearls) January 21, 2016