Start program in background (or start crontab ahead of time)

Hey!

I'm working on a script that will add a user, create some configfiles, and add a crontab for the user.

The crontab looks like the following:
@reboot /home/user/program config.conf &

I would like for this process to start at the end of my script under the corresponding username by either running the crontab ahead of time, or by making sure that the program is started as if the user was running it himself.

How do I do that?

Edit:
The script already does what i want, except for running the program.

---------- Post updated at 12:06 PM ---------- Previous update was at 11:52 AM ----------

Never mind.. sudo was the answer.. :o