Create data directory if not exists

src/utils.rs

@@ -67,6 +67,10 @@ pub fn get_submission_data(challenge: i32) -> Vec<Value> {
             json
         }
         Err(ref e) if e.kind() == std::io::ErrorKind::NotFound => {
+            // Create parent directory if not exists
+            if let Some(parent_dir) = std::path::Path::new(&submission_data_path).parent() {
+                fs::create_dir_all(parent_dir).unwrap();
+            }
             let mut file = File::create(&submission_data_path).unwrap();
             file.write_all(b"[]").unwrap();
             file.flush().unwrap();