I am wondering if there is a way in which users can create their own field options for a drop down menu. I am creating a website in which users need to select what courses their in, and as more users submit classes, the less new users will have to submit new classes. The new users would simply select a class that was previously generated by a prior user's input. It is important to use a drop down menu because if I use a text box, different users would reference that same class however with a different name, and I wouldn't be able to recognize the fact that they are the same.
So in a nut shell, how should I go about user generated field options on a drop down menu.
Thanks in advance.