In the Wendelin learning track this permission is granted to the user via
"chgrp SLAPUSER /dev/i2c-3". Because we don't know the particular
slapuser we have to add the permission to all users of the slapsoft
group. Because /sys/bus/i2c/devices/i2c-3 is a virtual directory and
we want to make sure that even after rebooting or unplugging /
replugging of the sensor the permission is still granted udev rules
have been added.