added book_detail.html to templates

bookshelf/templates/bookshelf/book_detail.html

+{%  extends 'base.html' %}
+
+{% block title %}{{ books.title }}{% endblock %}
+{% block header %}{{ books.title }}{%  endblock %}
+{% block content %}
+    <a href="http://127.0.0.1:8000/authors/{{ books.author.pk }}">{{ books.author }}</a><br>
+    <p>{{ books.publisher }}</p><br>
+    <p>{{ books.year_published }}</p><br>
+    <p>{{ books.ISBN }}</p><br>
+    <p>{{ books.blurb }}</p><br>
+    <a href="http://127.0.0.1:8000/homepage/">Home</a>
+    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
+    <a href="http://127.0.0.1:8000/books/">Books</a>
+    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
+    <a href="http://127.0.0.1:8000/authors/">Authors</a>
+{% endblock %}
\ No newline at end of file