Needs a user manual

[rvl]

There is no manual like what exists for nixpkgs haskell infrastructure.

• The manual should contain documentation for each of the use cases.
• It should show how and when to update the haskell.nix, hackage.nix and stackage.nix pins for client projects.
• Document the pkgSet structure.
• Document the mapping from derivation name to attribute in pkgSet structure.

[angerman]

See #46

[rvl]

The last two points were addressed in #179.