extract file extension from content-type when extension is missing
extension should return nil if file has no extension
Update fog.rb

Documentation comment update
Specs for file with no extension
Revert "Only return version url if version exists"

This reverts commit 2582999e83cde4b0ba3fdf4b132b1c8410502eb1.
Merge pull request #1248 from hasghari/missing-extension

missing file extension
Merge pull request #1253 from mzubala/patch-1

Fixed fog file extension method
CarrierWave::Storage::Fog::File#filename returns wrong part when the url contains '/' in query string
Make cache storage pluggable