This library is based off of the work of duelinmarkers, located at:

http://github.com/duelinmarkers/appengine-clj/tree/master

So far, the only part of that library that has been incorporated is the
datastore part. However, com.ubermensch.appengine-clj.datastore has been
enhanced to allow the storage and retrieval of collections of child Entities.

It supports this by looking for collections (sets, lists or vectors) of
maps with a ::key field and storing the Key and the type of collection (set,
list or vector) in a java.util.Collection, which AppEngine supports. When
an Entity with such a collection is retrieved, the library recognizes the Key's
and fetches the lot of them in a single batch. Currently, the maximum size
for the stored collection is 1000 Entities because AppEngine only allows you
to fetch 1000 results in a single get.