codeclimate/codeclimate-rubocop

This cop checks for uses of `DateTime` that should be replaced by
`Date` or `Time`.

### Example:

    # bad - uses `DateTime` for current time
    DateTime.now

    # good - uses `Time` for current time
    Time.now

    # bad - uses `DateTime` for modern date
    DateTime.iso8601('2016-06-29')

    # good - uses `Date` for modern date
    Date.iso8601('2016-06-29')

    # good - uses `DateTime` with start argument for historical date
    DateTime.iso8601('1751-04-23', Date::ENGLAND)