feat(promises): make sure chaining works

lib/promise.js

-var util           = require("util")
-  , Promise        = require("bluebird")
-  , EventEmitter   = require("events").EventEmitter
-  , proxyEventKeys    = ['success', 'error', 'sql']
-  , Utils          = require('./utils')
+var util            = require("util")
+  , Promise         = require("bluebird")
+  , EventEmitter    = require("events").EventEmitter
+  , proxyEventKeys  = ['success', 'error', 'sql']
+  , Utils           = require('./utils')
+  , INTERNAL        = function() {}
 
 var SequelizePromise = function(resolver) {
   var self = this;
@@ -28,7 +29,12 @@ var SequelizePromise = function(resolver) {
   }.bind(this));
 };
 
-util.inherits(SequelizePromise, Promise);
+util.inherits(SequelizePromise, Promise)
+
+// Need to hack then to make sure our promise is chainable
+SequelizePromise.prototype.then = function (didFulfill, didReject, didProgress) {
+  return this._then(didFulfill, didReject, didProgress, void 0, new SequelizePromise(function () {}), this.then);
+};
 
 SequelizePromise.prototype.on = function(evt, fct) {
   if (evt === 'success') {
@@ -72,6 +78,7 @@ SequelizePromise.prototype.emit = function(evt) {
  * @alias ok
  * @return this
  */
+
 SequelizePromise.prototype.success =
 SequelizePromise.prototype.ok = function(fct) {
   this.then(fct);

test/promise.test.js

@@ -421,6 +421,21 @@ describe(Support.getTestDialectTeaser("Promise"), function () {
       });
     });
 
+    it('should still work with .complete() after chaining', function(done) {
+      var spy = sinon.spy()
+        , promise = new SequelizePromise(function (resolve, reject) {
+          resolve('Heyo');
+        });
+
+      promise.then(function (result) {
+        return result+'123';
+      }).complete(function (err, result) {
+        expect(err).not.to.be.ok;
+        expect(result).to.equal('Heyo123');
+        done();
+      });
+    });
+
     it('should still work with .success() when emitting', function(done) {
       var spy = sinon.spy()
         , promise = new SequelizePromise(function (resolve, reject) {
@@ -514,8 +529,8 @@ describe(Support.getTestDialectTeaser("Promise"), function () {
 
     describe("proxy", function () {
       it("should correctly work with success listeners", function(done) {
-        var emitter = new SequelizePromise()
-          , proxy = new SequelizePromise()
+        var emitter = new SequelizePromise(function () {})
+          , proxy = new SequelizePromise(function () {})
           , success = sinon.spy()
 
         emitter.success(success)
@@ -531,8 +546,8 @@ describe(Support.getTestDialectTeaser("Promise"), function () {
       })
 
       it("should correctly work with error listeners", function(done) {
-        var emitter = new SequelizePromise()
-          , proxy = new SequelizePromise()
+        var emitter = new SequelizePromise(function () {})
+          , proxy = new SequelizePromise(function () {})
           , error = sinon.spy()
 
         emitter.error(error)
@@ -549,8 +564,8 @@ describe(Support.getTestDialectTeaser("Promise"), function () {
       })
 
       it("should correctly work with complete/done listeners", function(done) {
-        var promise = new SequelizePromise()
-          , proxy = new SequelizePromise()
+        var promise = new SequelizePromise(function () {})
+          , proxy = new SequelizePromise(function () {})
           , complete = sinon.spy()
 
         promise.complete(complete)
@@ -569,7 +584,7 @@ describe(Support.getTestDialectTeaser("Promise"), function () {
     describe("when emitting an error event with an array of errors", function() {
       describe("if an error handler is given", function() {
         it("should return the whole array", function(done) {
-          var emitter = new SequelizePromise()
+          var emitter = new SequelizePromise(function () {})
           var errors = [
             [
               new Error("First error"),