Function rubric::dropbox::open_with_arg

pub fn open_with_arg(arg: &str, port: u16) -> Option<LaunchError>

This is the same as open(), but it will only open the dropbox if you run the executable with the arg you provide.

The dropbox will open if the provided arg is anywhere in the arg vector, ie. position doesn't matter.

It's probably a good idea to put something that isn't obvious as the arg, perhaps a password. That way, no one will accidentally (or malicously) opens the dropbox.

// Must run the execuable with `my_grader open_sesame`
dropbox::open_with_arg(8080, "open_sesame");