Init fails when using 2.3.1 with OS X and rbenv
doc/prepare.md Says you can use 2.3.1 or later, but if you're using rbenv on OS X (maybe others?), it initializes the ruby-version file from the gitlab repo in the middle and looses all of the gems. Subsequent commands fail.
If I start with ruby 2.3.3, it all works fine.
Seems like the easiest way to fix this would be recommending 2.3.3 in doc/prepare.md