ASP.NET Core RC2 Seed Data using Services

I've been using ASP.NET 5 RC1 in which I've an application in which I seed administrative credentials into the data base using Services as follows:

public void ConfigureServices(IServiceCollection services)
    {
        services.AddEntityFramework()
                .AddSqlServer()
                .AddDbContext<ApplicationDbContext>(options => options.UseSqlServer(Configuration["Data:DefaultConnection:ConnectionString"]));

        services.AddIdentity<AdministratorUser, IdentityRole>()
            .AddEntityFrameworkStores<ApplicationDbContext>()
            .AddDefaultTokenProviders();

        services.AddMvc();

        services.AddTransient<AdministratorSeedData>();
    }

Here is the connection string sub-object:

 "ConnectionString": "Server=.;Database=kjanshair;Trusted_Connection=True;"

And the service that I use to seed data is being seeded using the Administrative seed data. It all works fine but when I port it to RC2, with the following changes in the startup as:

public void ConfigureServices(IServiceCollection services)
    {
        services.AddDbContext<ApplicationDbContext>(options => 
        options.UseSqlServer(Configuration["Data:DefaultConnection:ConnectionString"]));

        services.AddIdentity<ApplicationUser, IdentityRole>()
            .AddEntityFrameworkStores<ApplicationDbContext>()
            .AddDefaultTokenProviders();

        services.AddMvc();

        services.AddTransient<AdministratorSeedData>();
    }

with the connection string as:

"ConnectionString": "Server=.;Database=_CHANGE_ME;Trusted_Connection=True;"

I get an exception in Configure() method

public async void Configure(IApplicationBuilder app, AdministratorSeedData seeder)
    {
        app.UseIdentity();

        app.UseMvcWithDefaultRoute();

        await seeder.EnsureSeedData(); //Here exception occurs
    }

saying as:

Message = "Cannot open database \"_CHANGE_ME\" requested by the login. The login failed.\r\nLogin failed for user 'DESKTOP-55E4D9H\\Janshair Khan'."

Why Am I getting this error? I've looked all over the alternatives but couldn't resolved.