Added extension method BuildConfiguration

src/Volo.Abp.AspNetCore/Microsoft/Extensions/DependencyInjection/AbpAspNetCoreServiceCollectionExtensions.cs

@@ -1,4 +1,5 @@
 using Microsoft.AspNetCore.Hosting;
+using Microsoft.Extensions.Configuration;
 
 namespace Microsoft.Extensions.DependencyInjection
 {
@@ -8,5 +9,10 @@ namespace Microsoft.Extensions.DependencyInjection
         {
             return services.GetSingletonInstance<IHostingEnvironment>();
         }
+
+        public static IConfigurationRoot BuildConfiguration(this IServiceCollection services, string fileName = "appsettings")
+        {
+            return services.GetHostingEnvironment().BuildConfiguration(fileName);
+        }
     }
 }