Install Postgres and Runit service on Alpine Linux

Ideally used in conjunction with my Alpine Linux playbook, though it shouldn't be hard to adapt it to other systems.

Securing your postgres installation should go as follows:

root@alpine-dev /root # psql -U postgres  
psql (11.5)
Type "help" for help.

postgres=# \password
Enter new password: 
Enter it again: 
postgres=# \q
root@alpine-dev /root # sv down postgres
root@alpine-dev /root # sed -i.bak -e's/trust$/md5/g' /var/postgres/pg_hba.conf

Ideally add the password to your ~/.pgpass if you're going to do backups from cron or similar. This can be done by defining postgres_pgpass as found commented out in defaults/main.yml