Prosody fail to start on server with mysql backend

[Andor Kadar]

Prosody is failing to start, due the MySQL-server starting later than prosody.
The workaround has applied by adding 2 lines to /etc/init.d/prosody
# Should-Start: postgresql mysql
# Should-Stop: postgresql mysql

systemctl disable prosody.service
systemctl enable prosody.service

The next reboot the service is working as it should.

Description: Ubuntu 16.04.1 LTS
Release: 16.04
prosody:
  Installed: 0.9.10-1
  Candidate: 0.9.10-1
  Version table:
 *** 0.9.10-1 500
        500 http://archive.ubuntu.com/ubuntu xenial/universe amd64 Packages
        100 /var/lib/dpkg/status