Support Lerna and/or Yarn Workspaces

Created by: rovansteen

Are there any plans to support Lerna? By default Lerna uses the packages directory to store the packages. Right now the content of that folder is not transpiled so it's not possible to use ES6 code in there. It would be nice to have the possibility to use Lerna to create a monorepo application with create-react-app.

I've tried using the src directory with Lerna, but that conflicts with not ignoring node_modules directory inside the src directory, so it gives a ton of lint errors when you do so.