Added migration that corrects invalid columns.
Added migration that corrects invalid columns.

osbridge/openconferenceware,mynameisfashanu/openconferenceware,ondrocks/openconferenceware,osbridge/openconferenceware,ondrocks/openconferenceware,mynameisfashanu/openconferenceware,osbridge/openconferenceware,mynameisfashanu/openconferenceware,ondrocks/openconferenceware,ondrocks/openconferenceware,osbridge/openconferenceware,mynameisfashanu/openconferenceware