Install is broken

I'm trying to install hologram-agent on linux, but the mere method for building hologram seems broke. The ./hologram.sh build_all script tries to pull a container on dockerhub under the adroll/hologram_env repo except it doesn't exist, and when I try to build the image locally it fails to build due to gem install fpm --no-rdoc --no-ri failing to since it requires ffi requires Ruby version >= 2.3.

How are people installing hologram on linux? Or even macOS for that matter?

@BillMedernach as I've seen you made all of the commits recently, thanks.