adding psycopg2 in requirements.pip
--use-mirrors deprecated already, and fix syntax in requirement
revert back to adding ghost mongo
remove mongo from before install
Added the 50x.html file specified by the nginx config file but mysteriously missing from the repo
Merge branch 'slim_dedicated_server' into develop_ribalba

* slim_dedicated_server:
  Added the 50x.html file specified by the nginx config file but mysteriously missing from the repo
  remove mongo from before install
  revert back to adding ghost mongo
  --use-mirrors deprecated already, and fix syntax in requirement
  adding psycopg2 in requirements.pip