An error occurred while installing rugged

Following this tutorial [link] to install gitlab on a dedicated server. I need to :

sudo -u git -H bundle install --deployment --without development test postgres aws

But an error occurred while installing rugged :

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

    /usr/local/bin/ruby extconf.rb
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=/usr/local/bin/ruby


    Gem files will remain installed in /home/git/gitlab/vendor/bundle/ruby/2.0.0/gems/rugged-0.21.2 for inspection.
    Results logged to /home/git/gitlab/vendor/bundle/ruby/2.0.0/gems/rugged-0.21.2/ext/rugged/gem_make.out
    An error occurred while installing rugged (0.21.2), and Bundler cannot continue.
    Make sure that `gem install rugged -v '0.21.2'` succeeds before bundling.

So I installed rugged -> I installed CMake & config-pkg :

/home/git/gitlab$ sudo gem install rugged
Building native extensions.  This could take a while...
Successfully installed rugged-0.21.2
Parsing documentation for rugged-0.21.2
unable to convert "\xC0" from ASCII-8BIT to UTF-8 for lib/rugged/rugged.so, skipping
1 gem installed

But it doesnt change anything :

Errno::EACCES: Permission denied - /home/git/gitlab/vendor/bundle/ruby/2.0.0/gems/rugged-0.21.2/LICENSE
An error occurred while installing rugged (0.21.2), and Bundler cannot continue.
Make sure that `gem install rugged -v '0.21.2'` succeeds before bundling.

Any idea ?

For OSX if you're using homebrew:

brew install cmake 
bundle install

First, try installing cmake:

sudo apt-get install cmake

Then, repeat the command:

sudo -u git -H bundle install --deployment --without development test postgres aws

For me, gem was complaining about pkg-config missing dependence, so I did:

sudo apt-get install pkg-config

and then

sudo gem install rugged -v '0.22.2'

after that, I revert to my older version of gitlab and re-run the script for the upgrade.

My older version of gitlab was 6.9.2 and the upgraded version 8.0.5

Note: The above mentioned solutions did not work for me.

Here is the error log I got

checking for gmake... no
checking for make... yes
Building Rugged using system libraries.
libgit2 version is not compatible, expected ~> 0.99.0
*** 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.

It was mainly saying libgit2 version is not compatible, expected ~> 0.99.0

and I tried gem install rugged -v '0.99.0' and then bundle install.

then the problem is solved.