Docker documentation-nobody as user

I'd like to suggest that the default docker user id being assigned as 'nobody' be mentioned somewhere in the docker installation documentation.

This is breaking for some installation configurations (mine: small experimental lab with Portainer as root, which results in a container that looks running but isn't actually working...my level of frustration at struggling fo 2 hours to figure out why a container wont deploy, only to find an issue 7 years old, but undocumented without digging into git to find it.....)

I don't have the requisite experience or time to make a pull request on this.

My thought would be to use language like this: "While running Docker containers as root it not recommended, those running in this way should be aware that the container runs as user "nobody" by default. This will potentially cause permissions errors in certain deployment environments."

Locate the Docker installation documentation where container defaults are described; the issue does not name a specific file. Add a note explaining that containers run as user "nobody" by default and that this can cause permission errors in some deployment environments, then verify the wording in the rendered documentation.