scala – convert an integer to a date to count the number of days

I need to convert the format integer to date (yyyy-mm-dd) to calculate the number of days.

        registry date
20130826
20130829
20130816
20130925
20130930
20130926

Desired performance:

    registryDate TodaysDate DaysInBetween
20130826 2018-11-24 1916
20130829 2018-11-24 1913
20130816 2018-11-24 1926