new_contents: """brief response submitted at
  
  Revision ID: 760
  Revises: 750
  Create Date: 2016-10-24 14:16:29.951023
  
  """
  
  # revision identifiers, used by Alembic.
  revision = '760'
  down_revision = '750'
  
  from alembic import op
  import sqlalchemy as sa
  
  
  def upgrade():
      op.add_column('brief_responses', sa.Column('submitted_at', sa.DateTime(), nullable=True))
  
  
  def downgrade():
      op.drop_column('brief_responses', 'submitted_at')
  
subject: Add `submitted_at` migration to `brief_responses` table