class ActiveAdmin::Inputs::DatepickerInput

def datepicker_options
  options = self.options.fetch(:datepicker_options, {})
  options = Hash[options.map{ |k, v| [k.to_s.camelcase(:lower), v] }]
  { datepicker_options: options }
end

def input_html_options
  super.tap do |options|
    options[:class] = [options[:class], "datepicker"].compact.join(' ')
    options[:data] ||= {}
    options[:data].merge! datepicker_options
  end
end