fakes/fake.go
func (s *MockMongo) Upsert(selector interface{}, update interface{}) (info *mgo.ChangeInfo, err error) {
	err = s.Err
	return
}
func (s *MockMongo) Upsert(selector interface{}, update interface{}) (info *mgo.ChangeInfo, err error) {
	err = s.Err
	return
}
//Upsert -