update url patterns

[lukruh]

Django provided some new functionality for url patterns. Even if it's backward compatible, it would be nice to update it some when.
This is what djangos system check told me.

WARNINGS:
?: (urls.W002) Your URL pattern '/(?P<bot_token>.+?)/$' [name='webhook'] has a route beginning with a '/'. Remove this slash as it is unnecessary. If this pattern is targeted in an include(), ensure the include() pattern has a trailing '/'.

also update the include in the installation process.