Add prototype docker container

Beginning of #175

mentioned in issue #175

assigned to @pserwylo

Thanks @grote, I'll take a look at this tomorrow (e.g. 10hrs from now).

Other than the two comments above, this is working quite well for me. Happy to have it merged once those two changes are made.

resolved all discussions

Thanks for testing this @pserwylo!

When trying the npm install myself, I ran into some issues where one container tried to access another one that was not ready, so now I introduced a wait-for script that makes the containers wait on each other.

merged

Hmm, that is a little strange that you need to wait like that. I would have thought that docker-compose would have built/pulled all the containers first, then started them. However I'm no expert on this stuff, so don't really know how the tool works under the hood.

Sorry, I didn't explain myself sufficiently.

Docker-compose does indeed pull containers first and only starts them once they are fully available. It even starts them in the right order. However, it is possible that one is starting up faster than another one. The specific problem I ran into was at the first start with empty volumes where postgresql needed some time to initialize its database. The other two containers tried connecting to the database, but failed and then bailed out, so only the database was left running.

In a headless setup, this is of course undesired, so the wait-for script now waits for the database to become available until a timeout is reached.