how to make a link of 'http' with rails_admin

I am serching below page about how to make a link of 'http' http://api.rubyonrails.org/v5.2.0/classes/ActionDispatch/SSL.html

but I can`t find how to use "http". this is written how to use 'https'

please tell me howt set 'http' for link in the administrator page.