Build separate docker image for builder image

This should be an image without Capistrano, but with the built image.

• TODO: Do we need all of the image to deploy correctly? Or can we get away with a base Ruby install for Capistrano?

added pipeline label

added project label

We can split out dependencies by using Bundler groups

changed title from Build multiple docker images to Build separate docker image for builder image

changed milestone to %Build multiple docker images

removed project label

assigned to @jamietanna

This will also require the deployer image to be split out, but won't yet remove the built site, as #105 (closed) expects.

removed assignee

mentioned in merge request !32 (merged)

assigned to @jamietanna

closed via merge request !32 (merged)