added comment to use effect for fetching data

imports/ui/Home.jsx

@@ -18,13 +18,14 @@ export default function Home(props) {
     const [sensorCardValues, setSensorCardValues] = useState(updateCardValues);
     const [dataHistory, setDataHistory] = useState(props.dummyData); // for init data
 
-    // runs when the app mounts
+    // runs when the app mounts, similiar to componentDidMount and componentDidUpdate
     // if you give a prop to useEffect, it also runs each time this prop changes..
     useEffect(() => {
+        // const data = await fetch('api-address') // fetch data from db here and destructure it
         console.log("data is changing, start rerender..")
         setDataHistory(props.dummyData);
         setSensorCardValues(updateCardValues);
-    }, [props.dummyData])
+    }, [])
 
     // render the data
     // make sensorCarddeck responsive