**** CubicPower OpenStack Study ****
def upgrade(migrate_engine):
meta = MetaData()
meta.bind = migrate_engine
t = Table('bm_nodes', meta, autoload=True)
name_col = Column('instance_name', String(255))
t.create_column(name_col)
**** CubicPower OpenStack Study ****
def downgrade(migrate_engine):
meta = MetaData()
meta.bind = migrate_engine
t = Table('bm_nodes', meta, autoload=True)
t.drop_column('instance_name')