Add ability to use attributes in belongsTo and hasOne accessors

This will allow you to put attributes into the accessor requests.
It also complements the newly added field selectedValues so you can get
the exact fields you requested when using associations.

lib/associations/belongs-to.js

@@ -32,9 +32,16 @@ module.exports = (function() {
     var self     = this
       , accessor = Utils._.camelize('get_' + (this.options.as || Utils.singularize(this.target.tableName)))
 
-    obj[accessor] = function() {
+    obj[accessor] = function(params) {
       var id    = obj[self.identifier]
-      return self.target.find(id)
+      if(!Utils._.isUndefined(params)) {
+        if(!Utils._.isUndefined(params.attributes)) 
+          params = Utils._.extend({where: {id:id}}, params)
+      }
+      else 
+        params = id
+      
+      return self.target.find(params)
     }
 
     return this

lib/associations/has-one.js

@@ -37,12 +37,21 @@ module.exports = (function() {
   HasOne.prototype.injectGetter = function(obj) {
     var self = this
 
-    obj[this.accessors.get] = function() {
+    obj[this.accessors.get] = function(params) {
       var id    = obj.id
         , where = {}
 
       where[self.identifier] = id
-      return self.target.find({where: where})
+
+      if(!Utils._.isUndefined(params)) {
+        if(!Utils._.isUndefined(params.attributes)) {
+          params = Utils._.extend({where: where}, params)
+        }
+      }
+      else 
+        params = {where: where}
+
+      return self.target.find(params)
     }
 
     return this

spec-jasmine/associations/has-many.spec.js

@@ -87,11 +87,15 @@ describe('HasMany', function() {
         user.setTasks([task1, task2]).success(function() {
           user.getTasks().success(function(tasks) {
             expect(tasks.length).toEqual(2)
+            user.getTasks({attributes: ['title']}).success(function(tasks) {
+              expect(tasks[0].selectedValues.title).toEqual('task1')
+              expect(tasks[0].selectedValues.id).toEqual(null)
               done()
             })
           })
         })
       })
+    })
 
   it("should allow selfAssociation to be single linked (only one DAO is created)", function() {
     var oldLength = sequelize.daoFactoryManager.daos.length;

spec-jasmine/associations/has-one.spec.js

@@ -88,11 +88,15 @@ describe('HasOne', function() {
       user.setTask(task).on('success', function() {
         user.getTask().on('success', function(task2) {
           expect(task.title).toEqual(task2.title)
+          user.getTask({attributes: ['title']}).on('success', function(task2) {
+            expect(task2.selectedValues.title).toEqual('snafu')
+            expect(task2.selectedValues.id).toEqual(null)
             done()
           })
         })
       })
     })
+  })
 
   it("unsets unassociated objects", function() {
     var user, task1, task2;