If you read between the lines, all they're asking for is a site with dynamically generated pages, where some of the content comes from a database. The database can contain any info you want to stick in it

A forum is good, but unless they specifically said you need to write back to the database too, depending on how big the project is meant to be and how much time you've been given, it may be suitable, it may be overkill
You could be really lazy and have a database with one table with 2 keys in it, and all the php page does it take a value to look up in the first column, and spit out the matching result from the second or some error if not found

Of course, you learn less or put less skills into practice that way
