Ich möchte Restclient in Ruby installieren. Ich bekomme diese Meldung:nicht möglich, Restclient gem
Building native extensions. This could take a while...
ERROR: Error installing rest-client:
ERROR: Failed to build gem native extension.
current directory: /var/lib/gems/2.3.0/gems/unf_ext-0.0.7.4/ext/unf_ext
/usr/bin/ruby2.3 -r ./siteconf20170427-2260-1nc7gtz.rb extconf.rb
mkmf.rb can't find header files for ruby at /usr/lib/ruby/include /ruby.h
extconf failed, exit code 1
Gem files will remain installed in /var/lib/gems/2.3.0/gems/unf_ext-0.0.7.4 for inspection.
Results logged to /var/lib/gems/2.3.0/extensions/x86_64-linux/2.3.0/unf_ext-0.0.7.4/gem_make.out
Mein Terminal-Befehl war: sudo gem install rest-Client
Kann jemand mir helfen?