add crontab code example

Example 1: add new cron job in linux

For editing the cron job file : 
	crontab -e
    
For listing all the running cron job     
	systemctl status cron  ----OR----  crontab -l

Example 2: syntax crontab

# Example of job definition:
# .---------------- minute (0 - 59)
# |  .------------- hour (0 - 23)
# |  |  .---------- day of month (1 - 31)
# |  |  |  .------- month (1 - 12) OR jan,feb,mar,apr ...
# |  |  |  |  .---- day of week (0 - 6) (Sunday=0 or 7) OR sun,mon,tue,wed,thu,fri,sat
# |  |  |  |  |
# *  *  *  *  *  user command to be executed
example :
# 50 12 * * * ----- run every day at 12.50

# */5 * * * * ----- run every 5 minutes