Update OAuth2.md

OAuth2.md

@@ -61,6 +61,21 @@ GET https://accounts.google.com/o/oauth2/v2/auth?
 
 </details>
 
+
+<details>
+<summary><h3>HTTP Response</h3></summary>
+
+```bash
+HTTP/1.1 302 Found
+Location: https://xorismesiti.gr/api/auth/callback?code=4/0AX4XfWgNmGZVbV7Kdr8Q9yVyzIYBnbbBdLfX39ZaE8m0w8zT8jKRLl7w-uT8k7WiyLg0Q&state=random-state-value
+Content-Type: text/html; charset=UTF-8
+Content-Length: 0
+```
+
+</details>
+
+
+
 <details>
 <summary><h3>Frontent Code</h3></summary>