Replace timestamp column with attendance_time

 [server]
-uri=ws://localhost:3000
+uri=ws://13.124.104.70:3000
 [client]
 image_size=160
 margin=44
\ No newline at end of file

@@ -138,7 +138,7 @@ async def thread(websocket, path):
                 if verified_id != None:
                     # 인증 성공
                     # 오늘 이미 출석 됐는지 확인
-                    sql = "SELECT DATE(timestamp) FROM student_attendance WHERE (lecture_id=%s) AND (student_id=%s) AND (DATE(timestamp) = CURDATE());"
+                    sql = "SELECT DATE(attendance_time) FROM student_attendance WHERE (lecture_id=%s) AND (student_id=%s) AND (DATE(attendance_time) = CURDATE());"
                     cursor.execute(sql, ('0', verified_id))
                     # 출석 기록이 없는 경우에만
                     if cursor.rowcount == 0: