How To Download File In DWFX (AutoCad) Format In Rails Active Admin In Rails 4.2

Basically I am using gem 'activeadmin', github: 'Zhomart/active_admin', gem 'carrierwave-mongoid', :require => 'carrierwave/mongoid', branch: 'mongoid-old' and gem 'mini_magick'. I am trying to download Map Image in Autocad Format Like: icon.dwfx , icon.dwg or icon.dxf file extension.I have no idea how i can achieved this in rails.