Uploader changes based on https://github.com/carrierwaveuploader/carrierwave

app/uploaders/picture_uploader.rb

@@ -84,12 +84,12 @@ class PictureUploader < CarrierWave::Uploader::Base
 
   # Add a white list of extensions which are allowed to be uploaded.
   # For images you might use something like this:
-  def extension_white_list
+  def extension_whitelist
     %w(jpg jpeg gif png)
   end
 
   def content_type_whitelist
-    %r{/image\//}
+    /image\//
   end
 
   private