Django upgrade 1.10 -> 1.11 + all python and npm packages.
Do not forget to run
 npm install
 pip install -r requirements.txt

Also, recompile styling as a consequence of the bootstrap beta release.
 npm run webpack
 python manage.py collectstatic

Now users will be able to log in with their email as well as their username.
I make it implicit; I do not tell the user this in the login form, as I'm
not sure if the non-uniqueness of the `email` field could cause any problems.

I now built a rude try-catch to ease the login process for the user instead.