update documentation on requirements
update documentation on requirements

cdr-stats/cdr-stats,Star2Billing/cdr-stats,cdr-stats/cdr-stats,Star2Billing/cdr-stats,areski/cdr-stats,areski/cdr-stats,Star2Billing/cdr-stats,areski/cdr-stats,cdr-stats/cdr-stats,cdr-stats/cdr-stats,Star2Billing/cdr-stats,areski/cdr-stats