Add Bootstrap simple template and error handling

code/app/templates/admin.html

@@ -1,6 +1,7 @@
 {% extends "base.html" %}
 
 {% block content %}
-    <h1>Hi, {{ current_user.username }}!</h1>
+    <h1>Hey, {{ current_user.username }}!</h1>
     Do you want to nuke the database?
+    <li><a href="{{ url_for('nuke') }}">Yes, I want to burn down the world</a></li>
 {% endblock %}