[Authorize("Admin")]
public async Task<IActionResult> DeleteDItem(int? id)

"dependencies": {
  "BundlerMinifier.Core": "2.1.258",
  "Microsoft.ApplicationInsights.AspNetCore": "1.0.0",
  "Microsoft.AspNet.Authentication.Google": "1.0.0-rc1-final",
  "Microsoft.AspNetCore.Authentication.Cookies": "1.0.0",
  "Microsoft.AspNetCore.Authentication.Facebook": "1.0.0",
  "Microsoft.AspNetCore.Authentication.Google": "1.0.0",
  "Microsoft.AspNetCore.Authorization": "1.0.0",
  "Microsoft.AspNetCore.Diagnostics": "1.0.0",
  "Microsoft.AspNetCore.Diagnostics.EntityFrameworkCore": "1.0.0",
  "Microsoft.AspNetCore.Identity.EntityFrameworkCore": "1.0.0",
  ...
  "Npgsql.EntityFrameworkCore.PostgreSQL": "1.0.0"

public void ConfigureServices(IServiceCollection services)
{
  services.AddAuthorization(options =>
  {
    options.AddPolicy("Admin", policy =>
                               policy.RequireAuthenticatedUser());
  });
  services.AddIdentity<ApplicationUser, IdentityRole>()
          .AddEntityFrameworkStores<ApplicationDbContext>()
          .AddDefaultTokenProviders();
}

public void Configure(IApplicationBuilder app, IHostingEnvironment env,
                      ILoggerFactory loggerFactory)
{
  app.UseIdentity();
}

<sites>
            <site name="WebApplication2" id="4">
                <bindings>
                    <binding protocol="http" bindingInformation="*:12619:localhost" />
                </bindings>
            </site>
        </sites>

<sites>
            <site name="WebApplication2" id="4">
                <bindings>
                    <binding protocol="http" bindingInformation="*:12619:*" />
                </bindings>
            </site>
        </sites>