docs: add multiple user configuration example
docs: add multiple user configuration example

dgonyeo/ignition,coreos/ignition,coreos/ignition,AlexNPavel/ignition,higebu/ignition,AlexNPavel/ignition,dgonyeo/ignition,higebu/ignition,dgonyeo/ignition,ajeddeloh/ignition,ajeddeloh/ignition,coreos/ignition,ajeddeloh/ignition,higebu/ignition,AlexNPavel/ignition