pangloss/pacer — pull request #9 by pangloss (2011-12-28 21:36:20+00:00)
Title: Multi-key joins

Allow specifying a join with more than one key, for example:

```ruby
g.v.join.
key(:first_name) { |v| v[:first_name] }.
key(:last_name) { |v| v[:last_name] }.
join { |v| v.out(:hobbies) }
```