Allow configuration from gitlab.rb.
Allow configuration from gitlab.rb.

copystudy/omnibus-gitlab,gitlabhq/omnibus-gitlab,felixbuenemann/omnibus-gitlab,gitlabhq/omnibus-gitlab,copystudy/omnibus-gitlab,felixbuenemann/omnibus-gitlab,gitlabhq/omnibus-gitlab,felixbuenemann/omnibus-gitlab,copystudy/omnibus-gitlab,gitlabhq/omnibus-gitlab