Controller Scaffolding in MVC 6

hi folks,

I am referring to CRUD for controller and View with ASP.NET 5 and MVC 6.

Models/BookContext.cs:

public class BookContext : DbContext
    {
        public DbSet<Author> Authors { get; set; }
        public DbSet<Book> Books { get; set; }
    }    

Project.json

"dependencies": {
        ....................................    "EntityFramework.Core": "7.0.0-beta5","EntityFramework.SqlServer": "7.0.0-beta5","EntityFramework.Commands": "7.0.0-beta5","Microsoft.Framework.CodeGenerators.Mvc": "1.0.0-beta5"
    },"commands": {"web": "Microsoft.AspNet.Hosting --config hosting.ini","ef": "EntityFramework.Commands","gen" : "Microsoft.Framework.CodeGeneration"
    },

Config.json

{"Data": {"ConnectionString": "Server=(localdb)\\MSSQLLocalDB;Database=ContosoBooks123;Trusted_Connection=True;MultipleActiveResultSets=true"
  }
}

Startup.cs

.................................
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddMvc();

            services.AddEntityFramework()
                .AddSqlServer()
                .AddDbContext<BookContext>(options =>
                {
                    options.UseSqlServer(Configuration.Get("Data:ConnectionString"));
                });
        }
.................................

I have created a database after i run the data migrations command and it seems good. now i run the following command:
dnx . gen controller -name BookController --dataContext BookContext --model Book

I am getting error message but not just error message and it says:

Finding the generator 'controller'...
Running the generator 'controller'...
Attempting to figure out the EntityFramework metadata for the model and DbContext
No data stores are configured. Configure a data store by overriding OnConfiguring in your DbContext class or in the AddDbContext method when setting up services.

I do not understand. My Database Context is seem ok.
What am i missing?

Thanks in advance