Rugged gem installation issue possibly with lingit2 on Windows

I am using Windows and my gem file has this line:

gem 'rugged'

When i run bundle install on gemfile, it's giving me this error:

Installing rugged 0.21.0 with native extensions

Gem::Ext::BuildError: ERROR: Failed to build gem native extension.

C:/Ruby21/bin/ruby.exe extconf.rb --use-system-libraries checking for cmake... no ERROR: CMake is required to build Rugged.

* 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=C:/Ruby21/bin/ruby

extconf failed, exit code 1

Gem files will remain installed in C:/Ruby21/lib/ruby/gems/2.1.0/gems/rugged-0.2 1.0 for inspection. Results logged to C:/Ruby21/lib/ruby/gems/2.1.0/extensions/x86-mingw32/2.1.0/rug ged-0.21.0/gem_make.out An error occurred while installing rugged (0.21.0), and Bundler cannot continue.

Make sure that gem install rugged -v '0.21.0' succeeds before bundling.

I'm guessing it has something to do with libgit2 but I'm not sure.