Dockerfile cleanup
Add missing libraries
Fix confd configs
Update to 6.8
Update to 6.9
Upgrade to 7.0 and Ruby 2.1.2
Update postgresql (for pg_dump) to 9.3
Don't precompile when migrating
Fix HOME env variable, /etc/ssh to volume
Remove --gecos from useradd

Apparently using it can cause PAM: System error
on a certain kernel/docker version.
Remove subgit