Please explain how to use wordpress:cli

[mans0954]

Please could some documentation regarding use of the wordpress:cli image be added? Thanks.

[tianon]

The PR which added this has the suggested usage: docker-library/wordpress#198

The basic gist is that to interact with a WordPress install in the way that wp-cli does, one needs access to the on-disk files of the WordPress install, and access to the database (and the easiest way to accomplish that such that wp-config.php does not require changes is to simply join the networking context of the existing and presumably working WordPress container).

We definitely need a blurb about this, but I'd like to keep it as simple as possible (and leave extrapolation into more advanced use cases as an exercise for the reader).