Basic DB mapping
=================

[Data type derivation being a pivotal point of HRR, explain more in detail
 what HRR does at compile time and what the result looks like]


Full example
------------

[Take a table like e.g. users and explain all the stuff HRR generates via Template Haskell:
 the record data type, selectors, projections, and a basic relation that is equivalent to SELECT * FROM]


Projections
-----------

[Explain HRRs projections (:: Pi a b) and what they're useful for]


TypeMap
--------

[How to tell HRR to use custom type mappings, like mappings to different
  Haskell string/text or numeric types]