feat: check database is available when backend starts

[eamon0989]

When the backend is started, it should check if a database is connected, if not, a warning or error should be shown.

[medic-code]

I'll take this. I've just done a quick search and looks like you can use the docker engine API to know the status of the container is running. So should be relatively simple to ensure that we get that appropriate response and if not to throw an appropriate error message.

[medic-code]

Can I ask do you mean for local development or in production as well ? As the solution I was thinking of is for local development when running the docker container locally. It would some what depend on the architecture of the backend in production to how to implement in prod.