Adds shelf page

Works on #25

fedireads/templates/shelf.html

@@ -0,0 +1,10 @@
+{% extends 'layout.html' %}
+{% block content %}
+
+<div id="content">
+    <div>
+        <h2>{% include 'snippets/username.html' %} > {{ shelf.name }}</h2>
+        {% include 'snippets/shelf.html' with shelf=shelf ratings=ratings %}
+    </div>
+</div>
+{% endblock %}