added 404 page + prepared for production setup

templates/404.html

@@ -0,0 +1,13 @@
+{% extends "base.html" %}
+{% load static %}
+{% block title %}404 Not Found{% endblock %}
+{% block head %}
+    <link rel="stylesheet" href="{% static "error.css" %}">
+{% endblock %}
+{% block footer %}{% endblock %}
+{% block main %}
+    <div class="wrapper">
+        <h1 class="title">Page not found</h1>
+        <p class="desc">Oops, page <span class="url">{{ request.path }}</span> could not be found. Go back to <a href="{% url "dashboard" %}">Dashboard</a></p>
+    </div>
+{% endblock %}