Level 07

This exercise involves introducing a monad transformer (ReaderT) to our application. The use of the ReaderT in our application is motivated in part by the expansion of the number of inputs to the various functions involved in handling different requests.

Since nearly any given request handler will likely require access to either the general application configuration or the database, it is tedious to have to pass the information in manually in every instance.

Since we already have an AppM type, we're extending with more functionality, this is what is known as 'stacking' monad transformers.

The steps for this level:

1. src/Level07/AppM.hs
2. src/Level07/DB.hs
3. src/Level07/Core.hs