Added note for the Anular UI

docs/en/Authentication/Social-External-Logins.md

@@ -1,10 +1,8 @@
 # Social/External Logins
 
-## ASP.NET Core MVC / Razor Pages UI
-
 The [Account Module](../Modules/Account.md) has already configured to handle social or external logins out of the box. You can follow the ASP.NET Core documentation to add a social/external login provider to your application.
 
-### Example: Facebook Authentication
+## Example: Facebook Authentication
 
 Follow the [ASP.NET Core Facebook integration document](https://docs.microsoft.com/en-us/aspnet/core/security/authentication/social/facebook-logins) to support the Facebook login for your application.
 
@@ -27,4 +25,8 @@ context.Services.AddAuthentication()
     });
 ````
 
-> It would be a better practice to use the `appsettings.json` or the ASP.NET Core User Secrets system to store your credentials, instead of a hard-coded value like that. Follow the [Microsoft's document](https://docs.microsoft.com/en-us/aspnet/core/security/authentication/social/facebook-logins) to learn the user secrets usage.
+> It would be a better practice to use the `appsettings.json` or the ASP.NET Core User Secrets system to store your credentials, instead of a hard-coded value like that. Follow the [Microsoft's document](https://docs.microsoft.com/en-us/aspnet/core/security/authentication/social/facebook-logins) to learn the user secrets usage.
+
+## Angular UI
+
+Beginning from the v3.1, the Angular UI uses authorization code flow (as a best practice) to authenticate the user by redirecting to the MVC UI login page. So, even if you are using the Angular UI, social/external login integration is same as explained above and it will work out of the box.