module ActiveAdmin::Reloader

def self.to_complete(*args, &block)

Use ActiveSupport::Reloader if available for Rails 5, fall back to ActionDispatch::Reloader for earlier Rails

ActionDispatch::Reloader.to_cleanup is deprecated in Rails 5.0 and will be removed from Rails 5.1 
def self.to_complete(*args, &block)
  if defined? ActiveSupport::Reloader
    ActiveSupport::Reloader.to_complete(*args, &block)
  else
    ActionDispatch::Reloader.to_cleanup(*args, &block)
  end
end

def self.to_prepare(*args, &block)

Use ActiveSupport::Reloader if available for Rails 5, fall back to ActionDispatch::Reloader for earlier Rails

ActionDispatch::Reloader.to_prepare is deprecated in Rails 5.0 and will be removed from Rails 5.1 
def self.to_prepare(*args, &block)
  if defined? ActiveSupport::Reloader
    ActiveSupport::Reloader.to_prepare(*args, &block)
  else
    ActionDispatch::Reloader.to_prepare(*args, &block)
  end
end