eltiare/carrierwave-vips — pull request #3 by mariovisic (2012-08-08 11:17:36+00:00)
Title: Remove conversion to gif as it is not supported by ruby-vips.

ruby-vips does not have a gif converter class anymore (not sure if it did before?) so it will error out when trying to convert to gif.

You can see the available writer classes here: https://github.com/jcupitt/ruby-vips/blob/master/lib/vips/writer.rb#L235-262