rails new No es crea una aplicació nova

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rails new No es crea una aplicació nova

rails new No es crea una aplicació nova

 Gem::Ext::BuildError: ERROR: Failed to build gem native extension. current directory: /Users/stefan/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/nio4r-2.3.1/ext/nio4r /Users/stefan/.rbenv/versions/2.4.0/bin/ruby -r ./siteconf20190212-24856-1bhk2ja.rb extconf.rb checking for unistd.h... *** extconf.rb failed *** Could not create Makefile due to some reason, probably lack of necessary libraries and/or headers. Check the mkmf.log file for more details. You may need configuration options. Provided configuration options: --with-opt-dir --without-opt-dir --with-opt-include --without-opt-include=${opt-dir}/include --with-opt-lib --without-opt-lib=${opt-dir}/lib --with-make-prog --without-make-prog --srcdir=. --curdir --ruby=/Users/stefan/.rbenv/versions/2.4.0/bin/$(RUBY_BASE_NAME) /Users/stefan/.rbenv/versions/2.4.0/lib/ruby/2.4.0/mkmf.rb:457:in `try_do': The compiler failed to generate an executable file. (RuntimeError) You have to install development tools first. from /Users/stefan/.rbenv/versions/2.4.0/lib/ruby/2.4.0/mkmf.rb:588:in `try_cpp' from /Users/stefan/.rbenv/versions/2.4.0/lib/ruby/2.4.0/mkmf.rb:1095:in `block in have_header' from /Users/stefan/.rbenv/versions/2.4.0/lib/ruby/2.4.0/mkmf.rb:945:in `block in checking_for' from /Users/stefan/.rbenv/versions/2.4.0/lib/ruby/2.4.0/mkmf.rb:351:in `block (2 levels) in postpone' from /Users/stefan/.rbenv/versions/2.4.0/lib/ruby/2.4.0/mkmf.rb:321:in `open' from /Users/stefan/.rbenv/versions/2.4.0/lib/ruby/2.4.0/mkmf.rb:351:in `block in postpone' from /Users/stefan/.rbenv/versions/2.4.0/lib/ruby/2.4.0/mkmf.rb:321:in `open' from /Users/stefan/.rbenv/versions/2.4.0/lib/ruby/2.4.0/mkmf.rb:347:in `postpone' from /Users/stefan/.rbenv/versions/2.4.0/lib/ruby/2.4.0/mkmf.rb:944:in `checking_for' from /Users/stefan/.rbenv/versions/2.4.0/lib/ruby/2.4.0/mkmf.rb:1094:in `have_header' from extconf.rb:14:in `' To see why this extension failed to compile, please check the mkmf.log which can be found here: /Users/stefan/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/extensions/x86_64-darwin-16/2.4.0-static/nio4r-2.3.1/mkmf.log extconf failed, exit code 1 Gem files will remain installed in /Users/stefan/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/nio4r-2.3.1 for inspection. Results logged to /Users/stefan/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/extensions/x86_64-darwin-16/2.4.0-static/nio4r-2.3.1/gem_make.out An error occurred while installing nio4r (2.3.1), and Bundler cannot continue. Make sure that `gem install nio4r -v '2.3.1'` succeeds before bundling. run bundle exec spring binstub --all Could not find gem 'puma (~> 3.11)' in any of the gem sources listed in your Gemfile. Run `bundle install` to install missing gems. 

Vaig provar de crear una nova aplicació de Rails quan vaig rebre aquest error.

Vaig executar una nova cartera de rails per començar un projecte de cartera nou. Algú pot ajudar-me amb aquest error?

No estic segur de què cal cercar al missatge d'error anterior.

Estic fent servir macOS 10.14.2 si és útil

# rubí-sobre-rails