The Dockerfile can be optimized

- Build your code with `mhart/alpine-node:8 as api_nodejs`
- Copy in `mhart/alpine-node:slim-8 as final` from `api_nodejs` your built application
- Run application with `final`

https://registry.hub.docker.com/r/mhart/alpine-node/tags
https://github.com/Ealenn/Echo-Server/blob/master/Dockerfile