Reflexive relationships are not supported

[tylertreat]

What steps will reproduce the problem?

1. Created a domain class which has a relationship with itself.
2. Try to persist this entity.

What is the expected output? What do you see instead?
The ORM should be able to handle reflexive relationships, e.g. a class Category contains a collection of sub-categories implemented as List.

This may require a rather substantial overhaul of the ORM's relationship code.

[tylertreat]

Reflexive one-to-one and many-to-one relationships are supported for free. Issues have been added for reflexive many-to-many (issue #29) and one-to-many (issue #30).