But I want to change this model, so instead of redoing it like "rails
destroy .... -> rails generate scaffold...", all I need to do is to edit
the migration file above?
Or do I need to reproduce ANOTHER migration file like above and add
t.remove :text
???
I am a little confused because the migration file above has the
time-stamp, which indicates the time of execution (rake db:migrate).
So, does that mean the file above is useless unless I want to rollback?
Depends. If you haven't yet run rake db:migrate, you can just edit
the migration, but you need to know what you're doing if it's complex.
If you've already migrated, and you've used any new columns or tables
you've added, then you must create another migration. If you've
migrated but not used the new columns or tables, and it's a migration
that CAN be rolled back (not all can), you *can* roll it back (rake
db:rollback), fix it, and re-migrate... but you must be *very* certain
that your rollback won't lose you any data.
