Veraticus/Dynamoid — pull request #43 by afrojas (2012-05-09 19:39:03+00:00)
Title: Added a few helper finders

Made it a little more ruby-like to find a single object with a range key, so instead of
```ruby
User.find_by_id('someHashKey', {:range_key => 'someRangeKey'})
```
you can
```ruby
User.find_by_composite_key('someHashKey', 'someRangeKey')
```

Similarly added a helper to find all objects by hash and range
```ruby
User.find_all_by_composite_key('Jackson', range_greater_than: 1)
```