Add recipes of the day

Release v0.3 "Krippenspiel" and document previous Changes

Merge branch 'postgresql'

Rename all database FK columns from 'foo' to 'foo_id' #119

Closes #119.

Merge branch 'organizations'

Force numeric 'value's of ingredients and fix existing data

Merge branch 'anti-spam'

Rename "site admin" to "site owner"

I think we could have additional "site admins" in the future
but the "site owner" is currently and will be the highest
privilege level.

Add column 'is_archived' to projects

Add DATETIME column 'created' to projects and users