Support rails 6
Default the root_dir setting to Rails.root.to_s in Rails applications
Make the sprockets transformer extension configurable
Upgrade to support babel 7. If you need to use babel 6, you can still use Sprockets::BumbleD version 1.1
Defer execution of babel plugin and preset resolution until the first time Transformer#call is invoked.
This prevents an exception from being raised if the railtie is loaded before node modules have been installed.
As long as the babel packages are installed before call is invoked, you're good to go.
Support transforming to other module formats by adding transform_to_umd flag
Pass babel plugins and presets as absolute paths so that they can be found even when transpiling files outside the package.json subtree
This relies on methods introduced in babel-core 6.22.0 (babel/babel#4729)
Support rails 5
Switch to using register_engine to avoid sprockets regression (rails/sprockets#384)
Initial version