SQLite was having incompatibility issues with Ruby 1.9.3. This makes for a higher barrier to entry when testing carrier wave locally but ensure that tests can pass on TravisCI.
0.6.0 aims to remove code debt that we've accumulated over time to provide first-class support for the latest stuff. Storage backends: 0.6.x will support only :file and :fog for storage backends. Other backends (like gridfs with Mongoid) will only be supported via external gems. This should help alleviate the confusion caused by having multiple S3 and Cloudfiles backends. Rails support: Rails 3.2.0 and greater will be supported. Due to several changes in ActiveSupport and ActiveRecord since 3.0 plus deprecations already scheduled for 4.0, it's just not practical to support every Rails version in future releases. Aiming for a release of 0.6.0 alongside the release of Rails 3.2.0.
… issues are fixed