我正在使用 ASP.NET Core 2.0。下面是我的代碼。啟動：namespace foo{    public class Startup    {        public Startup(IConfiguration configuration)        {            Configuration = configuration;        }        public IConfiguration Configuration { get; }        // This method gets called by the runtime. Use this method to add services to the container.        public void ConfigureServices(IServiceCollection services)        {            // Add framework services.            services                .AddMvc()                .AddJsonOptions(options => options.SerializerSettings.ContractResolver = new DefaultContractResolver());            services.AddDbContext<fooContext>(options => options.UseSqlServer(Configuration.GetConnectionString("UserDatabase")));        }        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.        public void Configure(IApplicationBuilder app, IHostingEnvironment env)        {            if (env.IsDevelopment())            {                app.UseBrowserLink();                app.UseDeveloperExceptionPage();            }            else            {                app.UseExceptionHandler("/Home/Error");            }            app.UseStaticFiles();            app.UseMvc(routes =>            {                routes.MapRoute(                    name: "default",                    template: "{controller=Home}/{action=Index}/{id?}");            });        }    }}應用程序設置.json：{  "Logging": {    "IncludeScopes": false,    "LogLevel": {      "Default": "Debug",      "System": "Information",      "Microsoft": "Information"    },    "ConnectionStrings": {      "UserDatabase": "Server=DESKTOP-FSES7UK;Database=xxx;User Id=sa; Password=xxxxxxx;Trusted_Connection=True;"    }  }}如何修復它？