Make Asset Pipeline compatible with Chrome DevTools Autosave

https://github.com/NV/chrome-devtools-autosave doesn’t play nice with Asset Pipeline. https://github.com/NV/chrome-devtools-autosave/issues/27

The culprit of the problem is in the asset’s URLs. I cannot decipher a file path by its URL. For instance, /assets/main.css?body=1 could be either app/assets/stylesheets/main.css, lib/assets/stylesheets/main.css or vendor/stylesheets/main.css.

To fix it, we could either make URLs match their file path:

/app/assets/stylesheets/main.css?body=1

or introduce source-path query parameter:

/assets/main.css?body=1&source-path=app/assets/stylesheets/main.css

Any help would be good.