Cron support

[Alexey]

about security
when user add new job in crontab we can do this steps
a)
put username in line
for exam
*/15 * * * * vu2001 <comand>
it's means that command will started under vu2001

or when job adds to cron
run
crontab -u vu2001

it's will put comand into cron for user - vu2001 and run under his rights