Document cron job for removing deploy owned files older than 7 days

[bess]

We should have a shared practice where files in the /tmp directory that are owned by deploy are deleted after 7 days. Otherwise they start filling up the disk after awhile.

sudo find /tmp -type f -mtime +7 -user deploy -execdir rm -- '{}' ;

• Document setting up a cron job via whenever
• Documenting setting up this particular cron job