Matching function using PHP

So here is the deal:

I got this school project, a dating site. I just can't figure out a way to match users to each other. The users have a favourite music genre stored in the database and they need to be matched with each other

Example: user1 clicks matching button, php matches him to another user with the same favourite music genre and writes that somehow to the database.

My best guess is for both users a row named "match" wich has both their user id's stored.

I'm not quite sure.

Does someone know a way?