rails/rails — pull request #12389 by chancancode (2013-09-27 20:32:55+00:00)
Title: Deprecate numeric since ago

The user is expected to explicitly convert the value into an
AS::Duration, i.e. `5.ago` => `5.seconds.ago`

This will help to catch subtle bugs like:

```ruby
def recent?(days = 3)
self.created_at >= days.ago
end
```

The above code would check if the model is created within the last 3
*seconds*.

In the future, Numeric#{ago,until,since,from_now} should be removed
completely, or throw some sort of errors to indicate there are no
implicit conversion from Numeric to AS::Duration.