Thanks, nice work! A few things to consider:
* For people who use choosenim like me, it would be nice if compiler and
nimble could be excluded from the list of packages to be updated.
* An initial `nimble refresh` would make sure that the package list is
up-to-date before updating.
* Under Linux (and Mac OS?), adding `#!/<home directory>/.nimble/bin/nim e`
at the top of the file and setting its executable flag makes the script an
executable.
* A public git repo (e.g. on github) is probably a better way of getting
comments/improvements.
* Maybe adding the functionality to nimble itself would'nt be that much
harder than writing an external script.
