Re-initialize database
    
    The migration of 85906960545_event_search_key_and_type.py doesn't
    provide an approach for altering existing records to add new columns
    which don't allow NULL value, thus db upgrade fails when we do 'db
    upgrade', this blocks us to generate any future migration.
    
    Since there is no Freshmaker instance is deployed by now, we have no
    real data to be maintained, and with the existing schema we can't give
    reasonable 'search_key' and 'event_type', re-initialize the database is
    an easy solution to workaround this (compare to changing 'search_key'
    and 'event_type' to be nullable).