Objective-C and Ruby on Rails Expert

I am in need of a skilled developer who is proficient in both Objective-C and Ruby on Rails. The primary goal is to build a robust web application. While I did not specifically denote the functionalities I require, my expectations are high in regards to the capabilities of the final product. It is essential that the professional who takes on this project is able to anticipate basic development elements, such as user authentication and database integration. Ability to incorporate more advanced features, based on the nature of the application, would be highly beneficial.