Automatic generation of documentation for HackageDB

[Donald Bruce Stewart]

> Concerning the last question, there is already a list of ideas at [4],
> but maybe more ideas or requests are now arising.

Great work Sascha!

I'd like to be able to:

    * recategorise packages online,
            e.g. we have "Compilers/interpreters"
                         "Code generation"

                         "Composition"
                         "Control"
                         "Monads"

                         "Cryptography"
                         "Codec"

                         "Data"
                         "Data structures"

                         "Foreign"
                         "Language"
                         "Scripting"

                         "Interfaces"
                         "User interfaces"

        - a first step would be to warn, or prevent people creating new
          categories.

    * find all packages that depend on a package
            (the opposite of the current info about all packages a
            given package depends on)

            and use that info to rank by popularity

-- Don