Manipulate all the templates to use {% url %} templatetag instead of hard coded URLs.
{% extends 'base.html' %}
{% block title %}
{{textbook.name}}
{% endblock %}
{% block content %}
<h3>{{ textbook.name }}</h3>
{% if can_edit %}
<a href="{% url edit_textbook textbook.id %}">Edit Text book</a>
{% endif %}
{% if can_approve %}
<a href="{% url approve_textbook textbook.id %}">Approve Text book</a>
{% endif %}
<hr />created by <a href="{% url view_textbook textbook.created_by.id %}">{{ textbook.created_by.username }}</a>
on {{textbook.creation_datetime|date:"D d M Y"}} at {{textbook.creation_datetime|time:"H:i"}}<br />
<hr />
{% if textbook.tags.count %}
Tags:
{% for tag in textbook.tags %}
{{tag}}
{% endfor %}
<hr />
{% endif %}
{% if chapters %}
Chapters: <br />
<table>
{% for chap in chapters %}
<tr>
<td><a href="{% url view_task chap.id %}">{{chap.title}}</a> </td>
<td> {{chap.status}} </td>
</tr>
{% endfor %}
</table>
{% else %}
There are no chapters in this textbook as of now.<br />
{% endif %}
<hr />
{% if comments %}
comments:<br /><br />
{% for comment in comments %}
<a href="{% url view_profile comment.commented_by.id %}">{{ comment.commented_by.username }}</a>
on {{ comment.comment_datetime|date:"D d M Y"}} at {{comment.comment_datetime|time:"H:i"}} wrote:<br />
{{ comment.data|linebreaksbr }}<br />
{% endfor %}
{% endif %}
<hr />
{% if can_comment %}
Add comment:<br />
<form action="" method="post">
{% csrf_token %}
{{form.as_p}}
<input type="submit" value="Submit">
</form>
{% endif %}
{% endblock %}