Added udev rule and init.d script for allowing users of video group to control backlight

rules/91-backlight.rules

@@ -0,0 +1,3 @@
+SUBSYSTEM=="backlight", ACTION=="add", \
+	RUN+="/bin/chgrp video %S%p/brightness", \
+	RUN+="/bin/chmod g+w %S%p/brightness"

rules/backlight

@@ -0,0 +1,13 @@
+#!/sbin/openrc-run
+#Copyright (C) 2018 rexy712
+
+start() {
+	ebegin "Forcing intel_backlight to work correctly"
+	/bin/chgrp video /sys/class/backlight/intel_backlight/brightness
+	/bin/chmod g+w /sys/class/backlight/intel_backlight/brightness
+	eend $?
+}
+
+stop() {
+	eend ${ret}
+}