docker image size improvement

[valerianpereira]

docker image size improvement

[tarzanek]

thank you for the PR, small clarification needed how can this improve image size? (not being a docker expert, this is just a curious question, so I'd like to get enlightened on what I am missing)

[valerianpereira]

every command is a layer and every later makes up the images. Reducing the number of commands reduces the image size.

Some read: https://semaphoreci.com/blog/2016/12/13/lightweight-docker-images-in-5-steps.html

[tarzanek]

now that makes sense then, merging...