Sweet merciful goodness I think I have something working.
I have added the necessary column to :embeddable_hosts and updated the admin UI for inputting that field.
(I am not sure what the naming convention for this file should be, I went with 20170505_add_embed_class_name_to_embeddable_hosts.rb).
I just need to add the class_name to the embed erb template, but am not sure how to access it within the template. Any pointers?
Ideally I’d like to add it to the <html> tag of the embed as a class…