Some tricks required here to get the dependencies to work out, but we got it!!
Oh also, we move away from the rbenv in Ubuntu's package manager, because it doesn't support more recent Rubies like 2.4.10.
NOTE: This doesn't boot yet! There's something changed in the `devise` API that we'll need to fix!
```
/vagrant/config/initializers/devise.rb:46:in `block in <top (required)>': undefined method `encryptor=' for Devise:Module (NoMethodError)
```
But yeah, we navigated the gem upgrades, and also I ran `rake rails:update` and hand-processed the suggestions it had for our config files.
