Docker compose example

Exalate commented:

## Title

Docker compose example

## Description

Developers are using Docker compose to quickly spin up CRDB . There are existing documentation of Docker compose with CockroachDB from @dbist at https://blog.ervits.com/2019/12/running-cockroachdb-with-docker-compose.html.

When used within CI/CD, related components may find it necessary Docker compose to wait for adjacent containers to start until cockroach is ready to go. https://docs.docker.com/compose/startup-order/ was referenced as a method of waiting.

## Outline

- describe docker compose
- add an example of waiting CRDB is ready before starting dependent services

## Expected Audience

Developers

Jira Issue: DOC-487