Containerise Workhorse but keep it in the unicorn pod
Related to https://gitlab.com/charts/helm.gitlab.io/issues/50
Containers within the same pod can share volumes between each other. This makes it easy for us to meet the same criteria as embedding workhorse.
Difficulties
Not many, this should work fine, just take an extra day or two to setup vs embedding workhorse in the unicorn container.
Benefits
1. We will not need to rebuild workhorse when rails changes.
1. This aligns with the idea that we can eventually push these Docker builds back into their projects, to have them versioned and built with their projects.
1. Aligns better with microservice methodology, and fits better with our 'cloud-native' label