code: def upgrade():
      
      op.create_index(op.f('ix_access_actionsroles_role_id'),
                      'access_actionsroles', ['role_id'], unique=False)
      op.drop_constraint(u'fk_access_actionsroles_role_id_accounts_role',
                         'access_actionsroles', type_='foreignkey')
      op.create_foreign_key(op.f('fk_access_actionsroles_role_id_accounts_role'),
                            'access_actionsroles', 'accounts_role', ['role_id'],
                            ['id'], ondelete='CASCADE')
      op.create_index(op.f('ix_access_actionsusers_user_id'),
                      'access_actionsusers', ['user_id'], unique=False)
      op.drop_constraint(u'fk_access_actionsusers_user_id_accounts_user',
                         'access_actionsusers', type_='foreignkey')
      op.create_foreign_key(op.f('fk_access_actionsusers_user_id_accounts_user'),
                            'access_actionsusers', 'accounts_user', ['user_id'],
                            ['id'], ondelete='CASCADE')
docs: Upgrade database.