rimraf should be moved from dependencies to devDependencies

[ivanvs]

As title is suggesting I don't see any reason why rimraf library should be part of dependencies. It is dependency of prestart:prod script, but I don't see that we are using it anywhere else in project. So I would like to move it to devDependencies.

[kamilmysliwiec]

Feel free to move it to the devDependencies if it's what you actually need. In the starter, it's located in dependencies because it's one of the steps required to build a production-ready app (removing previously compiled code), however, it's not always the case (depends on how exactly you do want to serve your app).