Deploy as docker rather than a go application

It looks like you can now deploy things to Elastic Beanstalk as docker instances rather than using their choice of deployment options:

https://medium.com/@sommershurbaji/deploying-a-docker-container-to-aws-with-elastic-beanstalk-28adfd6e7e95

would allow:
 * Full customisation of nginx config
 * Better relation between the testing instance and the live instance (both using the same docker) 