I figured it out, with the help from this post: https://forum.fortinet.com/tm.aspx?m=112673
Guess, I didn't search the forums enough, didn't realize it was only showing posts from the last 30 days.
Just FYI -
In security profiles, under Advanced, then Web Rating Overrides, I created a new custom category, added the website(s) to that category, then in Web Filter Profile, I set that custom category to allow. Easy, now that I found out how to do it.