I’m trying to update the gems, but I came across this error:

Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension.

/usr/bin/ruby2.0 extconf.rb
mkmf.rb can’t find header files for ruby at /usr/lib/ruby/include/ruby.h

Gem files will remain installed in /home/openproject/.bundler/tmp/4367/gems/debug_inspector-0.0.2 for inspection.
Results logged to /home/openproject/.bundler/tmp/4367/gems/debug_inspector-0.0.2/ext/debug_inspector/gem_make.out

An error occurred while installing debug_inspector (0.0.2), and Bundler cannot continue.
Make sure that `gem install debug_inspector -v ‘0.0.2’` succeeds before bundling.

Can anyone help?