Migrate project to Django>1.8 and python3

[dhruvhacks]

This task must be done in small manageable PRs and so start from one end (say updating the settings) and keep progressing.
In this way, raise new issues and use Project Board for tracking them.

• Try deploying this project on a staging server in order to test the functionality/validity of every PR.
• You may create a checklist or work on unit tests alongside this project.
• This issue will be closed with completion of Project.