crontab entry to ensure crawler restarts if something goes wrong

[drevicko]

To ensure continuous crawling, here's a linux crontab entry that would check every 5 minutes to see if it's running:

*/5 * * * * campaigns_twitter_crawler/start_project_twitter_crawler.sh start >> campaigns_twitter_crawler/cronlog.txt

This entry expects campaigns_twitter_crawler to be a subfolder of the users home folder. If this works well, we should add it somewhere, either in the readme or as a comment in the respective launch scripts.