qiita-markdownをcloud9からherokuへデプロイ時にエラー

qiita-markdownのgemを利用したサンプルアプリを
Cloud9環境からherokuにデプロイしたいのですが、以下のエラーがでてしまい
うまくデプロイができません。

対応方法をアドバイスのほどお願いします。

gem install rugged -v '0.26.0'を実行。
http://qiita.com/noraworld/items/5984cdad9e7feedab594
に記載されている内容などは対応してみたのですが、一向に直らない状況です。

remote:        Gem::Ext::BuildError: ERROR: Failed to build gem native extension.
remote:        
remote:        current directory:
remote:        /tmp/build_761712b116815f909623cee3c928058f/vendor/bundle/ruby/2.3.0/gems/rugged-0.26.0/ext/rugged
remote:        /tmp/build_761712b116815f909623cee3c928058f/vendor/ruby-2.3.4/bin/ruby -r
remote:        ./siteconf20170806-281-v3z43y.rb extconf.rb
remote:        checking for gmake... no
remote:        checking for make... yes
remote:        checking for cmake... no
remote:        ERROR: CMake is required to build Rugged.
remote:        *** extconf.rb failed ***
remote:        Could not create Makefile due to some reason, probably lack of necessary
remote:        libraries and/or headers.  Check the mkmf.log file for more details.  You may
remote:        need configuration options.
remote:        
remote:        Provided configuration options:
remote:        --with-opt-dir
remote:        --without-opt-dir
remote:        --with-opt-include
remote:        --without-opt-include=${opt-dir}/include
remote:        --with-opt-lib
remote:        --without-opt-lib=${opt-dir}/lib
remote:        --with-make-prog
remote:        --without-make-prog
remote:        --srcdir=.
remote:        --curdir
remote:        --ruby=/tmp/build_761712b116815f909623cee3c928058f/vendor/ruby-2.3.4/bin/$(RUBY_BASE_NAME)
remote:        --with-sha1dc
remote:        --without-sha1dc
remote:        --use-system-libraries
remote:        
remote:        To see why this extension failed to compile, please check the mkmf.log which can
remote:        be found here:
remote:        
remote:        /tmp/build_761712b116815f909623cee3c928058f/vendor/bundle/ruby/2.3.0/extensions/x86_64-linux/2.3.0/rugged-0.26.0/mkmf.log
remote:        
remote:        extconf failed, exit code 1
remote:        
remote:        Gem files will remain installed in
remote:        /tmp/build_761712b116815f909623cee3c928058f/vendor/bundle/ruby/2.3.0/gems/rugged-0.26.0
remote:        for inspection.
remote:        Results logged to
remote:        /tmp/build_761712b116815f909623cee3c928058f/vendor/bundle/ruby/2.3.0/extensions/x86_64-linux/2.3.0/rugged-0.26.0/gem_make.out
remote:        
remote:        An error occurred while installing rugged (0.26.0), and Bundler cannot continue.
remote:        Make sure that `gem install rugged -v '0.26.0'` succeeds before bundling.
remote:        
remote:        In Gemfile:
remote:        qiita-markdown was resolved to 0.20.1, which depends on
remote:        github-linguist was resolved to 4.8.18, which depends on
remote:        rugged
remote:  !
remote:  !     Failed to install gems via Bundler.
remote:  !
remote:  !     Push rejected, failed to compile Ruby app.
remote: 
remote:  !     Push failed
remote: Verifying deploy....
remote: 
remote: !       Push rejected to secure-eyrie-83653.
remote: