1. The app requires a module to capture customer's registration and check the database if the preferred name is available and if it is generate the url and notify the customer that their registration is succesful and provide the link to their login page.
2. The app should also have functionality to authenticate the user at the login page and at first login create the subdomain by copying the files, folders and database.
3. With my experience in HTML5, JavaScript, ASP.NET, C#, Entity Framework, Web APIs, I can do this in three days.