Description of problem:

As part of the data migration for public view, we need to move category field from bz db to hwcert db.


Additional info:
Although category value should be saved in models table, we still need this field in cert_records table to save category value before a model record has been created in models table.  It can happen when a user input a new model, which won't be added into models table until the cert has become public (I discussed it with Rob and doing that we can avoid adding invalid models into models table)