Docker: Add .dockerignore file in guide

[tpreusse]

Without the .dockerignore file the npm modules installed inside the image possibly get overwritten by your local modules.

The overwriting happens here:

COPY . /usr/src/app

Given you have a node_modules folder locally.

[ryanmurakami]

Maybe just make this statement a little clearer, something like:
To prevent your local modules and debug logs from being copied onto your Docker image, create a .dockerignore file with the below contents:

Also, you should mention where this file will go.

[ryanmurakami]

LGTM. Thanks for making that change!

[tpreusse]

Thank you for reviewing.

[tpreusse]

How do you handle the update of translations?
The Ukrainian version seems to be just English:
https://github.com/nodejs/nodejs.org/blob/master/locale/uk/docs/guides/nodejs-docker-webapp.md
Should I change it there too?

There is also a Korean version:
https://github.com/nodejs/nodejs.org/blob/master/locale/ko/docs/guides/nodejs-docker-webapp.md

[ryanmurakami]

@tpreusse You can ping the projects here. Like this: @nodejs/nodejs-uk @nodejs/nodejs-ko

[outsideris]

I'm from nodejs-ko. We will update the Korean document after this PR merged.

[ghaiklor]

@denysdovhan @nodejs/nodejs-uk I think we need to update it after PR is merged as well.

[ryanmurakami]

@tpreusse Thanks for the contribution!