Build A Mobile App With A Chatroom

I am looking to build a mobile app with many features including a chatroom. The app will be similar to the following app: Forex Signals Trading App. It is an app with a orange icon. Please download it and review all the features first before applying. There will be many key differences with my app. You must have be a talented app designer/developer. It would be preferred if you have created a chatroom where different users can talk. Please provide examples of your past work. Thank you.