Removing schedule model etc.

This was essentially an excercise in removing an unnecessary scaffold
and related database table. This is not a trivial thing to do.
For future reference, I think at least the following actions are
involved:

 * Drop the database table
 * rails destroy scaffold scaffold_name
 * Also delete (probably with git rm) all the remaining migrations
   that concern the particular table (not sure if these are deleted
   as part of the rails destroy command)
 * Good friends: rake db:migrate:reset and rake db:migrate