[Observium] automating svn update

Hello,

How to automate SVN update ?

In crontab im adding this:

#svn update 5 5 * * * root "cd /opt/observium/;svn update >> /dev/null 2>&1"

#after svn upadte 5 9 * * * root /opt/observium/discovery.php -u >> /dev/null 2>&1

but seems like first line doesn't work.

Any help?