Undefined Method Error with drjekyll list (using Ruby 2.5.5)

[mtpiercey]

> drjekyll list
drjekyll/1.0.1 on Ruby 2.5.5 (2019-03-15) [x86_64-linux]
drjekyll/1.0.1 on Ruby 2.5.5 (2019-03-15) [x86_64-linux]
GET https://github.com/drjekyllthemes/themes/raw/master/themes.yml

*** error: undefined method `downcase' for nil:NilClass

[geraldb]

Thanks for trying drjekyll and reporting the error.