docs: update docs for the oauth plugin

Author: yaroslav8765

adminforth/documentation/docs/tutorial/07-Plugins/11-oauth.md

@@ -350,4 +350,31 @@ Links to adapters:
 [Google](https://github.com/devforth/adminforth-google-oauth-adapter)
 [GitHub](https://github.com/devforth/adminforth-github-oauth-adapter)
 [Facebook](https://github.com/devforth/adminforth-facebook-oauth-adapter)
-[Keycloak](https://github.com/devforth/adminforth-keycloak-oauth-adapter)
+[Keycloak](https://github.com/devforth/adminforth-keycloak-oauth-adapter)
+
+
+## Fill user full name
+
+If you have a fullName field in your users resource, you can add it to the plugin setup:
+
+```ts
+
+plugins: [
+  ...
+
+  new OAuthPlugin({
+
+    ...
+
+    userFullNameField: 'fullName'
+
+    ...
+
+  }),
+]
+
+```
+
+This field will be automatically filled with the name that the provider returns, if this field was empty.
+
+> ☝️Not all providers return full name or even if they do, there is no guarantee that they will be correct