We need guidance on how to get this working within Docker.

[andrewculver]

I'm not Docker-y, so forgive my lack of understanding how people normally use that in a development environment, but there are two steps here:

1. Configure your Capybara driver to connect to Chrome on the host machine. I know that's doable because I work on projects where that happens.
2. The test process that's running within Docker needs to be able to write files to the same machine where the IDE is being run (e.g. the host). I mean... surely that's already happening? Otherwise, how do people run things like rake db:migrate and have it update the repo where they're doing commits and pushes from?

I'll leave this for someone who uses Docker for development.