(WIP) Add news article feature

It's good practice to keep the format string in the I18n config - http://guides.rubyonrails.org/i18n.html#adding-date-time-formats

Doing so will ensure we have consistent formatting across the application:

```yml
# config/locales/en.yml
en:
  date:
    formats:
      short: "%d %b %Y"
```
```rb
# app/decorators/news_article_decorator.rb
def formatted_date
  h.l(object.date, format: :short)
end
```