small changes

Back-End/src/main/java/com/zipline/back/controller/PostController.java

@@ -28,8 +28,8 @@ public class PostController {
     ) {
         post.setUser(userRepo.findByGithubId(githubId));
         post.setTimestamp(LocalDateTime.now());
+        post.setSender(githubId);
         return postRepo.save(post);
-
     }
 
     @GetMapping("/{githubId}")