gistfile1.js

function test(req, res) {
  //get the userId and...
  //
  req.models.addedRealEstate.exists({userId: userId, realEstateId: realEstateId})
  .then(function(recordExists) {
    //If record its exists, stop here else create record in db
    if(personIsActive) { return res.json('Error'); }
  }).then(function() {
    return req.models.addedRealEstate.create({userId: userId, realEstateId: realEstateId, source: source});
  }).then(function(realEstate) {
    return res.json('Success');
  });
}