title: undefined method 'each_pair' with openstruct
body: <p>I'm using OpenStruct to manipulate a json like this: <code>OpenStruct.new '{"age":100,"name":"name"}'</code> and I'm getting </p>
  
  <p><code>
  NoMethodError:
         undefined method `each_pair' for "{\"age\":100,\"name\":\"name\"":String
  </code></p>
  
  <p>this piece of code was working some time ago, and now it's not.</p>
  
  <p>I'm using Ruby 2.1</p>