class ActiveAdmin::ResourceDSL

def csv(options = {}, &block)


end
column :name
csv col_sep: ";", force_quotes: true do

end
column("Author") { |post| post.author.full_name }
column :name
csv do

For example:

Configure the CSV format 
def csv(options = {}, &block)
  options[:resource] = config
  config.csv_builder = CSVBuilder.new(options, &block)
end