Instead of using documents to add data to an index you can use Hashes and Arrays. The only real benefits of using a Document over a Hash are pretty printing and the boost attribute. You can add the boost attribute to Hashes and arrays using the BoostMixin. For example;

   class Hash
     include BoostMixin
   end

   class Array
     include BoostMixin
   end

   class String
     include BoostMixin
   end