Student or Learner
A policeman says:
"Tom and I will be colouring in our morning tea roster and Lisa will be at a front desk."
What does it mean "to colour in the morning tea roster"?
They have a chart showing what time of day various duties are to be carried out, and who is to do them, and they are colouring in the slots that they are expected to fill.
It's another word for timetable.