[PD-507] Scheduled partner library to be updated every week on sunday

Just wanted to automate this task.  If you see the related jira ticket, you'll see that this is only been updated once in the last 3 weeks, hence why I'm not worried about running this daily. I also chose Sunday so that it wouldn't mess with any tasks that need to run throughout the work week. Given the nature of this, I'm unable to actually test. 
http://celery.readthedocs.org/en/latest/userguide/periodic-tasks.html#crontab-schedules

Just specifying day_of_week, this is going to run every minute on Sunday.