📝 Docs: update oauth app section (#126)

Co-authored-by: Ju4tCode <42488585+yanyongyu@users.noreply.github.com>

Author: BhuwanPandey

README.md

@@ -101,7 +101,7 @@ user: PublicUser | PrivateUser = resp.parsed_data
 data: dict = github.graphql("{ viewer { login } }")
 ```
 
-### Develop an OAuth APP with web flow
+### Develop an OAuth APP (GitHub APP) with web flow
 
 ```python
 from githubkit.versions.latest.models import PublicUser, PrivateUser
@@ -119,6 +119,15 @@ auth: OAuthTokenAuthStrategy = github.auth.as_web_user("<code>").exchange_token(
 access_token = auth.token
 refresh_token = auth.refresh_token
 # restore the user token from database
+
+# when using OAuth APP or GitHub APP without user-to-server token expiration
+user_github = github.with_auth(
+    OAuthTokenAuthStrategy(
+        "<client_id>", "<client_secret>", token=access_token
+    )
+)
+# OR when using GitHub APP with user-to-server token expiration
+# you can use the refresh_token to generate a new token
 user_github = github.with_auth(
     OAuthTokenAuthStrategy(
         "<client_id>", "<client_secret>", refresh_token=refresh_token
@@ -128,6 +137,9 @@ user_github = github.with_auth(
 # now you can act as the user
 resp = user_github.rest.users.get_authenticated()
 user: PublicUser | PrivateUser = resp.parsed_data
+
+# you can get the user login id now
+login_id = user.login
 ```
 
 ### Develop an OAuth APP with device flow