Importing the correct DBSession in pshell with development.ini
Removing post.is_read column. This value should be calculated for each user, not everybody.
Adding an empty string as the default for Post.ancestry
Reinstating the default lazy load on Post.content
Adding method Discussion.posts()

It returns a list of posts with the given `parent_id`, sorted by the
Post.content.creation_date of their youngest descendant.
Adding method Post.responses()
Making Discussion.posts more efficient when there is a parent_id parameter
Changing 'organizational unit' to 'actor'.
Merge branch 'develop' of https://github.com/ImaginationForPeople/assembl into velruse
Still unsure about name of class

Conflicts:
	assembl/auth/models.py
still work in progress