Update the Devcontainer definition to include Redis

[rofrano]

As a Developer
I need my local development environment to include Redis
So that I can test the service locally with no Internet connection required

Assumptions:

• The docker-compose.yml file will add Redis while building the environment
• We can use a Redis Docker image
• alpine:redis should be used to keep the vm small

Acceptance Criteria:

Given I have started Visual Studio Code and Reopened in a Container
When I issue `docker ps` in a separate shell
Then I should see a `redis` instance running