Explicitly register Paperclip data URI adapter

See:
- thoughtbot/paperclip#2435
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-0889

Author: buren

config/initializers/paperclip.rb

@@ -12,3 +12,5 @@
   paperclip_path = "spec/test_files/#{paper_part}"
   Paperclip::Attachment.default_options[:path] = paperclip_path
 end
+
+Paperclip::DataUriAdapter.register