Add error pages

templates/403.html

@@ -0,0 +1,13 @@
+{% extends "base.html" %}
+
+{% load i18n %}
+
+{% block content %}
+    <h1>{% trans "Permission denied" %}</h1>
+    {% blocktrans %}You don't have the right to perform this request.{% endblocktrans %}
+    {% if exception %}
+        <div>
+            {% trans "Exception message:" %} {{ exception }}
+        </div>
+    {% endif %}
+{% endblock %}