new_contents: # Licensed under the Apache License, Version 2.0 (the "License"); you may
  # not use this file except in compliance with the License. You may obtain
  # a copy of the License at
  #
  #      http://www.apache.org/licenses/LICENSE-2.0
  #
  # Unless required by applicable law or agreed to in writing, software
  # distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
  # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
  # License for the specific language governing permissions and limitations
  # under the License.
  
  import sqlalchemy as sql
  
  from keystone.common import sql as ks_sql
  
  def upgrade(migrate_engine):
      meta = sql.MetaData()
      meta.bind = migrate_engine
  
      policy_table = sql.Table('policy', meta, autoload=True)
      rule_table = sql.Table('rule', meta, autoload=True)
      extra = sql.Column('extra', ks_sql.JsonBlob.impl)
      
      policy_table.create_column(extra)
      rule_table.create_column(extra)
  
subject: add extra column to policy and rule table