Problemas con json

he seguido todos los pasos de instalacion Versiones para Güindous( sorry ya me cambio luego a otro de linux)
ruby 2.1.6p336
Rails 4.3. Pero:

new rails Primer

An error occurred while installing json (1.8.2), and Bundler cannot continue.

Make sure that gem install json -v '1.8.2' succeeds before bundling.

You have not told us what the error was, there should be some more
detail. If it was a problem building then probably you have not
installed all the required tools. You need to tell us which operating
system you are using (Ubuntu, Mac os or whatever).