added and formatted books.html

bookshelf/templates/bookshelf/books.html

+{%  extends 'base.html' %}
+
+{% block title %}My Favorite Books{% endblock %}
+{% block header %}RJ's Favorite Books{%  endblock %}
+{% block content %}
+    {% for books in books %}
+        <a href="http://127.0.0.1:8000/books/{{ books.pk }}">{{ books.title }}</a><br>
+    {%  endfor %}
+{% endblock %}
\ No newline at end of file