Add error pages

templates/500.html

@@ -0,0 +1,8 @@
+{% extends "base.html" %}
+
+{% load i18n %}
+
+{% block content %}
+    <h1>{% trans "Server error" %}</h1>
+    {% blocktrans %}Sorry, an error occurred when processing your request. An email has been sent to webmasters with the detail of the error, and this will be fixed soon. You can now drink a beer.{% endblocktrans %}
+{% endblock %}