Goal $ rails server が動くように therubyracerがないって怒られた $ gem install therubyracer Fetching: libv8-3.16.14.3-x86_64-linux.gem (100%)^[[A Successfully installed libv8-3.16.14.3-x86_64-linux Building native extensions. This could take a while... ERROR: Error installing therubyracer: ERROR: Failed to build gem native extension. /usr/bin/ruby2.0 extconf.rb checking for main() in -lpthread... yes creating Mak