new_contents: """Add status index to task table.
  
  Revision ID: 2c49f64c0d4a
  Revises: 43397e521791
  Create Date: 2016-09-29 15:45:51.104377
  
  """
  
  # revision identifiers, used by Alembic.
  revision = '2c49f64c0d4a'
  down_revision = '43397e521791'
  
  from alembic import op
  
  
  def upgrade():
      op.create_index('idx_task_status', 'task', ['status'], unique=False, postgresql_concurrently=True)
  
  
  def downgrade():
      op.drop_index('idx_task_status', table_name='task')
  
subject: Add index to Task.status