To ensure it is unique on the main host (i.e., outside the container). Get rid
of devcontainer_initialize.sh, all it did was run "mkdir". Something this
trivial can be inlined in the devcontainer.json (less indirection this way).
The previous name, 'johncolvin/bluetradingsystems', was chosen in a
misguided effort to adhere to a naming convention recommended by Docker
Hub (https://docs.docker.com/docker-hub/repos/create/). In hindsight,
this convention isn't well suited to our use case. Our images are shared
by multiple users (e.g., sparkd dev users all use the same sparkd-dev
image), so it doesn't make sense to name the repository after an
arbitrary user.
Leave the image's default user as 'root' so we can modify the non-root user's
uid/gid. This is a common technique used in containers to gain file permissions
in mounted dirs.
The default user's uid/gid can't be changed because a bash process runs under
their ownership as long as the container is up. A user's uid/gid cannot be
changed while that user owns a process (at least not via 'usermod').
John Colvin