multi_json error

Gemfile

source "https://rubygems.org"

gem "multi_json"
gem "oj"
gem "json"

# Gems included by the bundle:
#   * bundler (1.3.4)
#   * json (1.8.0)
#   * multi_json (1.7.6)
#   * oj (2.0.14)

output

$ ./test.rb
/Users/chetan/.rvm/gems/ruby-2.0.0-p195/gems/multi_json-1.7.6/lib/multi_json/adapter.rb:35:in `collect_load_options': undefined method `[]' for nil:NilClass (NoMethodError)
  from /Users/chetan/.rvm/gems/ruby-2.0.0-p195/gems/multi_json-1.7.6/lib/multi_json/adapter.rb:25:in `load'
	from /Users/chetan/.rvm/gems/ruby-2.0.0-p195/gems/multi_json-1.7.6/lib/multi_json.rb:132:in `load'

test.rb

#!/usr/bin/env ruby

require "multi_json"

# MultiJson.load_adapter(:json_gem).activate! # fixes error
puts MultiJson.load("{}", :adapter => :json_gem)