def is_runnable?(direction)
      self.class.rerunnable_safe? || 
      (direction == UP && status.current_status < status_complete) || 
      (direction == DOWN && status.current_status > 0)
    end
def is_runnable?(direction)
      self.class.rerunnable_safe? || 
      (direction == UP && status.current_status < status_complete) || 
      (direction == DOWN && status.current_status > 0)
    end
Checks if a migration can be run