正式環境的資料庫.

總共有幾題會報告.

獲得當日12點時間戳.

use user_id and s_id search user's reports.

true => study group is exist.

test database.

更新study group 人數狀態並且回傳舉辦時間.

return true mean problem exist.

不存在指定的report return true.

if studygroup update, remeber also update new studygroup turn && old studygroup next turn value.

leetcode api data struct.