Summary
-------

The `comment` cube provides threadable comments feature.

Usage
-----

This cube creates a new entity type called `Comment` which could basically be
read by every body but only added by application's users.
It also defines a relation `comments` which provides the ability to add a
`Comment` which `comments` a `Comment`.

To use this cube, you want to add the relation `comments` on the entity type
you want to be able to comment. For instance, let's say your cube defines a
schema for a blog. You want all the blog entries to be commentable.
Here is how to define it in your schema:

.. sourcecode:: python

    from yams.buildobjs import RelationDefinition
    class comments(RelationDefinition):
        subject = 'Comment'
        object = 'BlogEntry'
        cardinality = '1*'

Once this relation is defined, you can post comments and view threadable
comments automatically on blog entry's primary view.
