Add templatetags for listing textbooks.
This templatetag must be refactored to be utilized for tasks also.
<h2>{{ title }}</h2>
<h3>List of textbooks open for contribution</h3>
<ul>
{% for task in tasks %}
<li>
<a href="{% url view_textbook task.id %}">
{{ task.title }}
</a>
</li>
{% endfor %}
</ul>
<br />