update the postReducer function to return fetched posts

Author: vishalnagda1

src/reducers/postReducer.js

@@ -1,4 +1,5 @@
 import { FETCH_POSTS, NEW_POST } from "../actions/types";
+import { act } from "react-dom/test-utils";
 
 const initialState = {
   items: [],
@@ -7,6 +8,11 @@ const initialState = {
 
 export default function (state = initialState, action) {
   switch (action.type) {
+    case FETCH_POSTS:
+      return {
+        ...state,
+        items: action.payload,
+      };
     default:
       return state;
   }