I have a simple model having some attributes. One of those
an overall grade, which I don't want users to be able to edit it on
their own. I display all the info in the database using a scaffold.
However, while scaffolding, I can see and edit the grade attribute,
which I only want to be displayed.
Just edit the erb files the scaffold generator (and don't forget to
enforce that people should be allowed to edit grades, you may want to
look at attr_accessible/attr_protected )