Changes that made it work for me, mostly

[adamhooper]

A few things have changed in DocumentCloud that haven't been reflected in documentcloud-vagrant.

Judging from the diff, I:

• upgraded Vagrantfile syntax
• used a default Ubuntu image instead of the mythical documentcloud.box
• upgraded to Postgres 9.3
• set a 2GB minimum on the VM, because bundle install crashes with the default 512MB.
• added gem install passenger
• upgraded Ruby to 2.0 in passenger config
• changed config/server to config/server/files in lots of places

Don't get me wrong: I haven't made documentcloud-vagrant fantastic. And I haven't documented what I did to finally get documentcloud up and running. But I've cleared up some of the bugs I encountered.