magic.js

schema.virtual('magic').set(function (v) {
  this.magic = v;
});

schema.pre('save', function (next) {
  if (!this.magic) return next();
  this.model('Other')
  .findOne({ magic: this.magick }).select('_id').exec(function (err, other) {
    if (err || !other) return next(err);
    self._owner = other._id;
    next();
  });
});