Added export functionality. Pending change of the path in export.sh

For the functionality to run properly you need to modify the path of scripts/export.sh and add a crontab for the update every 24h of the file feedback.csv.
The cron can be like this(with your PATH), everyday at 6 o´clock:
# m h dom mon dow command
* 6 * * * sh /Users/mariopl/Repositorios/firefoxos-dogfood/scripts/export.sh