Add login page

Change-Id: I167f6492aa2608558bf2ac4e6604dd584de6db66

src/App.js

@@ -1,7 +1,9 @@
 import React from "react";
 import { Admin, Resource, resolveBrowserLocale } from "react-admin";
 import polyglotI18nProvider from "ra-i18n-polyglot";
+import authProvider from "./synapse/authProvider";
 import dataProvider from "./dataProvider";
+import LoginPage from "./components/LoginPage";
 import germanMessages from "./i18n/de";
 import englishMessages from "./i18n/en";
 
@@ -16,7 +18,12 @@ const i18nProvider = polyglotI18nProvider(
 );
 
 const App = () => (
-  <Admin dataProvider={dataProvider} i18nProvider={i18nProvider}>
+  <Admin
+    loginPage={LoginPage}
+    authProvider={authProvider}
+    dataProvider={dataProvider}
+    i18nProvider={i18nProvider}
+  >
     <Resource name="data" />
   </Admin>
 );