我用firebase做了一个todo应用程序。我把todos存储在firestore里，并把添加todo的用户的电子邮件地址保存到文档里。但是当一个用户保存todo时，所有的用户都能看到那个todo。我的代码：

const [dailys, setDailys] = useState([]);
const dailyRef = firebase.firestore().collection('daily');
const [addDaily, setAddDaily] = useState('');
const email = firebase.auth().currentUser.email;

useEffect(() => {
    async function check() {
        dailyRef.orderBy('createdAt', 'desc')
            .onSnapshot(
                querySnapShot => {
                    const dailys = []
                    querySnapShot.forEach((doc) => {
                        const { heading } = doc.data()
                        dailys.push({
                            id: doc.id,
                            heading,
                            email: email,
                        })
                    })
                    setDailys(dailys)
                }
            )
    }
    check()
}, [])
const addDailyPlan = () => {
    if (addDaily && addDaily.length > 0) {
        const timeStamp = firebase.firestore.FieldValue.serverTimestamp();
        const daily = {
            email:email,
            heading: addDaily,
            createdAt: timeStamp
        };
        dailyRef
            .add(daily)
            .then(() => {
                setAddDaily('');
                Keyboard.dismiss();
            })
            .catch((error) => {
                alert(error);
            })
    }
}
render(
 <FlatList data={dailys}/>

）