new_contents: from alembic import op
  import sqlalchemy as sa
  
  
  """empty message
  
  Revision ID: 91351a73e6e2
  Revises: 63262fe95b9c
  Create Date: 2018-03-08 15:34:22.391417
  
  """
  
  # revision identifiers, used by Alembic.
  revision = '91351a73e6e2'
  down_revision = '63262fe95b9c'
  
  
  def upgrade():
      # ### commands auto generated by Alembic - please adjust! ###
      op.add_column('interventions', sa.Column('subscribed_events', sa.Integer()))
      op.execute('UPDATE interventions SET subscribed_events=0')
      op.alter_column('interventions', 'subscribed_events', nullable=False)
      # ### end Alembic commands ###
  
  
  def downgrade():
      # ### commands auto generated by Alembic - please adjust! ###
      op.drop_column('interventions', 'subscribed_events')
      # ### end Alembic commands ###
  
subject: Add bitmask for subscribed events to intervention table.