# this move is about adding a authority x user many to many relation ship for modelling PIs
# that is to say users who can vouch for other users in the authority, and
# can create slices

from sqlalchemy import Table, MetaData, Column, ForeignKey
from sqlalchemy import Integer, String

metadata = MetaData()

# this is needed by migrate so it can locate 'records.record_id'
records = \
    Table('records', metadata,
          Column('record_id', Integer, primary_key=True),
          )

# authority x user (PIs) association
authority_pi_table = \
    Table('authority_pi', metadata,
          Column('authority_id', Integer, ForeignKey(
              'records.record_id'), primary_key=True),
          Column('pi_id', Integer, ForeignKey(
              'records.record_id'), primary_key=True),
          )


def upgrade(migrate_engine):
    metadata.bind = migrate_engine
    authority_pi_table.create()


def downgrade(migrate_engine):
    metadata.bind = migrate_engine
    authority_pi_table.drop()