Finished common section of app

ref-test/app/templates/404.html

@@ -0,0 +1,8 @@
+{% extends "components/base.html" %}
+
+{% block content %}
+    <h1>Page Not Found</h1>
+    <p>
+        The page you were looking for does not exist. Try going back and navigating to the desired destination correctly.
+    </p>
+{% endblock %}