def upgrade():
    # ### commands auto generated by Alembic - please adjust! ###
    op.alter_column('users', 'expiry_date', new_column_name='expiry_ts')
    op.alter_column('users', 'joining_date', new_column_name='joining_ts')
    op.alter_column('users', 'last_login_date', new_column_name='last_login_ts')