Added multi-engine support to database.yml: sqlite, mysql, postgresql.
Added multi-engine support to database.yml: sqlite, mysql, postgresql.

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