Add TopicList component

diskuy/src/TopicList.js

+import React, { useEffect, useState } from "react";
+import axios from 'axios'
+import { Link } from "react-router-dom"
+
+const LINK = 'http://localhost:4000';
+
+export default function TopicList(props){
+    const [topics, setTopics] = useState([])
+
+    useEffect(() => {
+        const fetch = async () => {
+            const response = await axios.get(`${LINK}/api/topics`)
+            setTopics(response.data.data)
+        }
+        fetch()   
+    }, [])
+
+    return (
+        <div>
+            <ul>
+                {topics.map((value) => (
+                <li>
+                    <Link to={`/topic/${value.id}`}>{value.name}</Link>
+                </li>
+            ))}
+            </ul>
+        </div>
+    )
+}
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