﻿Overview
========

An identifier group is an uniquely named collection of zero or more aggregate identifiers that 
share a common property or state.

These groups can be passed through a query definition (explicitly or implicitly) to predefine which
aggregate identifiers the underlying projection of the query definition will be run.  This is useful in
order to define queries in a business-meaningful manner rather than having explicitly to specify the 
attribute-rule filters.

Note that this library is kept separate from the core "Event Sourcing" library as identifier groups
are not a core idea in every event sourcing implementation.  This library is, however, totally dependent 
on the underlying interfaces provided by the event sourcing library.
