Users can upload new journalists

Trello: https://trello.com/c/v0ua84y2/88-enable-csv-journalist-uploads

![journalist-import](https://cloud.githubusercontent.com/assets/4560985/5345328/fa3a743a-7ee4-11e4-9e54-31143dfb1940.gif)

Future refactoring idea: make a method `journalist_hash_from` that takes in a row and returns the hash that you pass to `find_or_create_by`. Then your code becomes:

```ruby
Journalist.find_or_create_by(journalist_hash_from(row))
```