Rather than terraforming Mars, wouldn't it be easier to 'manoeuvre' Ceres into an orbit around the Earth?

It sure is crazy.But lets just say your plan does work then what would we do with it.It is just a lump of rock.Mars might be habitable because it has a few things which are useful to us.eg water.Ceres is no different than the moon except that it is smaller.So it is a waste of time.Anyway,did you think about what will happen when we bring it to earth.If you want to put it into earth's orbit would be very difficult.Even if we miscalculate a tiny bit,that asteroid would go out into space or come crashing down to earth and kill all life.So,it is not worth the risk.And an asteroid has very weak gravity for us to be there comfortably and the weak gravity wold also let go of all that atmosphere which we put in.Even mars has difficulty hangng on to that little air it has.