What's the significance of the .ghci file?

[DestyNova]

While trying to replicate this setup in an existing Stack project, I noticed stack exec sensei test/Spec.hs fails to find the test modules. Then I noticed that I didn't have a .ghci file, and copied the one in this repo, which fixed the problem.

Could you add a note in the README perhaps explaining the function of this file? I'm guessing the following line is important and tells ghci to look in both the src and test directories for modules:

:set -isrc -itest