fix attachment uploader for aws

app/uploaders/attachment_uploader.rb

@@ -8,6 +8,15 @@ class AttachmentUploader < CarrierWave::Uploader::Base
   end
 
   def image?
-    %w(png jpg jpeg).include?(file.extension)
+    img_ext = %w(png jpg jpeg)
+    if file.respond_to?(:extension)
+      img_ext.include?(file.extension)
+    else
+      # Not all CarrierWave storages respond to :extension
+      ext = file.path.split('.').last
+      img_ext.include?(ext)
+    end
+  rescue
+    false
   end
 end