Using `sudo` within a script is generally considered poor practice, so
by default an error message is printed when the user attempts to perform
a write operation without sufficient permissions.
One way to deal avoid this error message is to alias `hosts` to `sudo
hosts`, but this then requires `sudo` for all operations and not just
write operations.
The new `--auto-sudo` option flag provides a way to automatically invoke
a write command with `sudo` when the user doesn't have write
permissions.
In order to provide cleaner documentation for this option, include more
option documentation in README.md.
