User.findByIdAndUpdate({ _id : userId, 'vehicle._id' : vehicleId },{ $push : { reg_number : reg_number,
                  category : category, model_year: model_year, insurance_date:insurance_date, tax_date:tax_date,
                  vehicle_name:vehicle_name }}, function(err, vehicle){

                if(err) { throw err }
                req.flash('success','Updated');

                //res.render('dashboard/vehicleUpdate', {vehicle});
              });