I have always used RabbitMQ in the past, and this seems to be a great alternative for many reasons. Being able to reply an entire log from a point in time would be an amazing feature to build systems on top of.
Haven't used Elixir in awhile, it has come a long way in a very short time. It is nice to see a good concurrent alternative to Node.js developing. Node is great, but it lacks that great framework that Rails brought to Ruby.
Great takeaways for using rails inside of docker and handling configuration options.