We have prepared the meal itself: the database. We have done the bulk of the job and in principle met (almost) all our objectives for the course.
Now we can engage in the preparation of a side-dish: the gravy. The database itself is a working product, ready for use, just like a plate of boiled potatoes is ready for use.
But after the easy step of upsizing it, it will be even better, just like a plate of potatoes will be better with a ladle or two of gravy poured atop of it.
We can rephrase
Now for the gravy...
as
Now let's see what additional job we can do to make the database better.