There are two new item types 'question' and 'rumor'.
Item types for GeoPoll data are 'question'.
Item types for RapidPro data are 'rumor'

remove unused import and fix pep8 white space

https://trello.com/c/Q9hEiE20/83-change-categories-available-to-match-those-specified-in-the-story

I think the version of the models you get for migrations doesn't include
the methods we defined, so the save method doesn't set slug
from name. So I have added explicit name and made the old
name, which was in slug format, into the value of slug.