send message to slack channel on failure

related to comments on #315

fix broken prepended domain links

monkeypatch relational models to allow generics
fix #109, as it is the beginnings of adding types

redo of 454cfc4e

This reverts commit 454cfc4e.

remove https from gitlab url

add python-gitlab package to requirements
add gitlab variables to settings
add advance repos django command

remove https from gitlab url

add python-gitlab package to requirements
add gitlab variables to settings
add advance repos django command