Update redux state management

Use immer with native javascript objects instead of immutablejs.

frontend/js/components/list/details.js

@@ -14,9 +14,10 @@ import { Runtime } from "../details/runtime";
 import { Title } from "../details/title";
 
 const ListDetails = (props) => {
-  if (props.data === undefined) {
+  if (!props.data || Object.keys(props.data).length === 0) {
     return null;
   }
+
   if (props.loading) {
     return null;
   }

frontend/js/components/shows/list.js

@@ -51,7 +51,7 @@ const ShowList = ({ match, history }) => {
     history.push("/shows/details/" + imdbId);
   };
 
-  let selectedShow = Map();
+  let selectedShow = new Map();
   if (selectedImdbId !== "") {
     selectedShow = shows.get(selectedImdbId);
   }