starting pgbouncer on startup
It turns out that I was putting my pidfile in /var/run which is fine for running it but when server is rebooted the file is deleted and pgbouncer can't find the file and it gives the this error

FATAL @src/main.c:553 in function write_pidfile(): /var/run/pgbouncer/pgbouncer.pid: No such file or directory


So simply moving the file to another location and chown the directory was all that was needed

$ sudo mkdir ~/pgbouncer
$ sudo chown -R postgres:postgres ~/pgbouncer