token_birth_ts in people table is modified when linkedin token is generated/refreshed
adding number of valid days for linkedin tokens to conf
adding a python module to check for token validity
return those leads only whose tokens are not expired
few comments are added for elaboration
fetch random lead only from the list of leads whose tokens are not expired yet
modifications to app.conf
separate module for sending alerts
adding alert module : my_alerts.py
changes to cronjob
adding cron_tokens_validity to app
merging sangram's code