"""Add date_modified for project

Revision ID: 8a5d68f74beb

Revises: 27a79ff0fb41

Create Date: 2017-07-18 19:28:09.566997

"""

from alembic import op

import sqlalchemy as sa

# revision identifiers, used by Alembic.

revision = '8a5d68f74beb'

down_revision = '27a79ff0fb41'

def upgrade():

    ''' Add the column date_modified to the table projects.

    '''

    op.add_column(

        'projects',

        sa.Column('date_modified', sa.DateTime, nullable=True,

                  default=sa.func.now())

    )

    op.execute("UPDATE projects SET date_modified=date_created;")

    op.alter_column(

        'projects',

        column_name='date_modified',

        nullable=False,

        existing_nullable=True)

def downgrade():

    ''' Remove the column date_modified from the table projects.

    '''

    op.drop_column('projects', 'date_modified')