He resigned his position at Newcastle United eight months ago.
The Monkey Hangers are second bottom of League Two, with far and away the worst defensive record in the entire league.
It has been a nose-drive for the club in the last two seasons and they face the prospect of non-league football next season unless someone can stop the rot.
The club appointed former player Paul Murray as manager with Donachie being appointed as his number two.
He resigned from Newcastle in February of this year after it was alleged that he'd punched reserve team player Remi Streete following a 2-0 defeat against Sunderland in an under-21 game.