Update 'Dockerfile'

Dockerfile for Airsonic
diff --git a/root/etc/s6.d/airsonic b/root/etc/s6.d/airsonic
Jan Christian Grünhage 12da6692f9 Update 'Dockerfile'		pirms 2 gadiem
root/etc/s6.d/airsonic	inital impl	pirms 3 gadiem
.drone.yml	temporarily migrate to docker hub	pirms 2 gadiem
Dockerfile	Update 'Dockerfile'	pirms 2 gadiem
LICENSE	Initial commit	pirms 3 gadiem
README.md	inital impl	pirms 3 gadiem