Add custom header for has_many form in Active Admin

some_recource.rb

# in any ActiveAdmin Resource you need in form block add the following code
# change 'translations' with your association name

  f.has_many :translations  do |translation|    
    translation.inputs("Caption"){} # Adding caption for languages
    translation.inputs(""){} # Spacer
    translations.input # add necessary inputs here 
  end