* Tweak to active total migrations * Formatting * Expose trait * Remove empty pre_ and post_upgrade hooks. Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io> Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io> Co-authored-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>