Forget about forms and controllers initially, just think about how to
store the data in the database. The rest can come later. One option
would be use a bit field for the selections, so A would be represented
by binary 001, B by 010, C by 100 and so on, then for A and B the
value would be 011. I believe there are gems available that will
handle this for you though I have not used them. Google for
shows a number of hits that look useful.
I’m hoping to play around with Rails and Adhearsion but I find it very
hard to get started. Does anybody know about a good starting point on
the web or perhaps an example application code, perhaps on git?