Update Advanced.md

- HaskellDB/HDBC: Not so much the existing packages per se, but the concept of never leaving our beloved type system to interact with other systems. Unleash the Monad!
- Fun readings: I think it would be great to compile a list of suggested readings that a student can check after the class. I put two of Mark Jones' papers there because I think they demonstrate how fun it is to work with Haskell (and they also serve as "capstones" of sorts).