Creating modules simply as needed.

[Sean Chalmers]

With #23 comes a good time to include a discussion about the benefit of making a new module as needed. It's straightforward to do, and can be very useful for slicing up your functionality as required.

[Sean Chalmers]

Added mention of this

applied-fp-course/src/Level04/Types.hs

Line 35 in dd90752

 -- Notice how we've moved these types into their own modules. It's cheap and