Entity framework does not create mdf file

In my ASP.net MVC5 project it creates the default database by Visual Studio 2013.

I went to the App_Data folder and deleted the mdf file from the database as well as the log file.

I'm wanting it to re-create this file.

In my configuration file, I have the following code.

   public class UserDBContext: DbContext 
    {

        public UserDBContext(): base("ConnectionString") 
        {
            Database.SetInitializer<UserDBContext>(new CreateDatabaseIfNotExists<UserDBContext>());

        }
        public DbSet<Cliente> Clientes{ get; set; }
        public DbSet<Topico> Topicos{ get; set; }
    }

It passes, and does not give any error, however it does not create the database file.