added cron example

cron-example

+# DO NOT EDIT THIS FILE - edit the master and reinstall.
+# (/tmp/crontab.ehsxLz/crontab installed on Sat Mar 24 05:32:56 2018)
+# (Cron version -- $Id: crontab.c,v 2.13 1994/01/17 03:20:37 vixie Exp $)
+# Edit this file to introduce tasks to be run by cron.
+# 
+# Each task to run has to be defined through a single line
+# indicating with different fields when the task will be run
+# and what command to run for the task
+# 
+# To define the time you can provide concrete values for
+# minute (m), hour (h), day of month (dom), month (mon),
+# and day of week (dow) or use '*' in these fields (for 'any').# 
+# Notice that tasks will be started based on the cron's system
+# daemon's notion of time and timezones.
+# 
+# Output of the crontab jobs (including errors) is sent through
+# email to the user the crontab file belongs to (unless redirected).
+# 
+# For example, you can run a backup of all your user accounts
+# at 5 a.m every week with:
+# 0 5 * * 1 tar -zcf /var/backups/home.tgz /home/
+# 
+# For more information see the manual pages of crontab(5) and cron(8)
+# 
+# m h  dom mon dow   command
+3 3 * * * cd /home/ubuntu && python2 oerupartners/oerupartners.py
+