rewrite frontend and logic in core app

core/templates/registration/logged_out.html

@@ -0,0 +1,11 @@
+{% extends "core/base.html" %}
+
+{% block navi %}
+    <a href="{% url 'admin:index' %}">admin</a>
+    |
+    <a href="{% url 'login' %}">login</a>
+{% endblock %}
+
+{% block content %}
+    You have been logged out.
+{% endblock %}