[Fixed]-How to add checkboxes to a list in html/django

Since you use Django, one way would be to take advantage of what Django provides for forms.
Here are the examples from the official doc, for version 1.10:

-for the radio buttons:
https://docs.djangoproject.com/en/1.10/ref/forms/widgets/#widgets-inheriting-from-the-select-widget

-for the form:
https://docs.djangoproject.com/en/1.10/topics/forms/#building-a-form-in-django

A django form uses the form tag.