Aufgabe 3: kleinere fixes

src/main/webapp/category.jsp

@@ -10,7 +10,7 @@
     response.setCharacterEncoding(StandardCharsets.UTF_8.name());
     String idValue = request.getParameter("id");
     Category category;
-    Database db = Database.getInstance();
+
     if (idValue == null) {
 %>
 <div class="m-container">
@@ -21,6 +21,7 @@
 <%
 } else {
     long id = Long.valueOf(idValue);
+    Database db = Database.getInstance();
     category = db.getCategory(id);
     if (category != null) {
 %>

src/main/webapp/index.html

@@ -7,6 +7,7 @@
 <ul>
     <li><a href="preview">Grobspezifikation</a></li>
     <li><a href="booklist">Backend</a></li>
+    <li><a href="categories.jsp">Kategorienübersicht</a></li>
 </ul>
 </body>
 </html>