Added documentation on adding configuration providers to 1.x to 2.0 Migration Document

aspnetcore/migration/1x-to-2x/index.md

@@ -98,6 +98,20 @@ The adoption of this new 2.0 pattern is highly recommended and is required for p
 ```
 Unable to create an object of type '<Context>'. Add an implementation of 'IDesignTimeDbContextFactory<Context>' to the project, or see https://go.microsoft.com/fwlink/?linkid=851728 for additional patterns supported at design time.
 ```
+## Adding Additional Configurations
+
+In 2.0 projects, the boilerplate configuration code is done behind the scenes. By default, Environment Variables and Application Settings are loaded into startup so all that is required in *Startup.cs* is initializing `IConfiguration` with the injected instance. To add additional providers, or change the existing providers, utilize `ConfigureAppConfiguration` on `IWebHostBuilder` in *Program.cs*. The setup is similar to Core 1.x
+
+````
+ var host = new HostBuilder()
+                .ConfigureAppConfiguration((hostContext, config) =>
+                {
+                    config.AddEnvironmentVariables();
+                    config.AddJsonFile("appsettings.json", optional: true);
+                    config.AddCommandLine(args);
+                })
+````
+
 
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