documentation and fixed a typo

include/cereal/archives/json.hpp

@@ -283,7 +283,7 @@ namespace cereal
                         even cout! */
       JSONInputArchive(std::istream & stream) :
         InputArchive<JSONInputArchive>(this),
-        itsReadStream(is)
+        itsReadStream(stream)
       {
         itsDocument.ParseStream<0>(itsReadStream);
         itsValueStack.push_back(itsDocument.MemberBegin());

sandbox_json.cpp

@@ -294,6 +294,15 @@ int main()
     std::cout << "---------------------" << std::endl << str << std::endl << "---------------------" << std::endl;
   }
 
+  {
+  cereal::JSONOutputArchive archive( std::cout );
+  bool arr[] = {true, false};
+  std::vector<int> vec = {1, 2, 3, 4, 5};
+  archive( CEREAL_NVP(vec),
+           arr );
+  }
+
+
   //{
   //  std::ifstream is("file.json");
   //  cereal::JSONInputArchive iar( is );