Pada kelas ImageUploader terdapat sebuah class method yang bernama self.[] # https://github.com/shrinerb/shrine/blob/master/lib/shrine.rb#L98-L102 class Shrine # ... module ClassMethods # ... def Attachment(name, **args) self::Attachment.new(name, **args) end alias attachment Attachment alias [] Attachment # ... end # ... end Thank you...

#!/usr/bin/env ruby puts "Hello world!"