Example site is offline

[caioramosps]

This link is offline http://rad-example.herokuapp.com/

[rakvium]

@caioramosps it might be connected to commit b65559c that removed :json from format configuration for the example project, though commit ab3c6b7 suggests that :json option is safe to be added back after #382 is resolved.

Adding :json option back locally worked fine, thus created a pull request: #501