Is Nokogiri required for bundling [ODOT Project]? Error when bundling.

group :development, :test do
    gem 'rspec-rails', '~> 2.0'
end

group :test do
    gem 'capybara', '~> 2.1.0'
end

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

    /Users/myname/.rbenv/versions/2.1.2/bin/ruby extconf.rb 
Building nokogiri using packaged libraries.
-----
libiconv is missing.  please visit http://nokogiri.org/tutorials/installing_nokogiri.html for help with installing dependencies.
-----
*** 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=/Users/guled/.rbenv/versions/2.1.2/bin/ruby
    --help
    --clean
    --use-system-libraries
    --enable-static
    --disable-static
    --with-zlib-dir
    --without-zlib-dir
    --with-zlib-include
    --without-zlib-include=${zlib-dir}/include
    --with-zlib-lib
    --without-zlib-lib=${zlib-dir}/lib
    --enable-cross-build
    --disable-cross-build

extconf failed, exit code 1

Gem files will remain installed in /Users/myname/.rbenv/versions/2.1.2/lib/ruby/gems/2.1.0/gems/nokogiri-1.6.2.1 for inspection.
Results logged to /Users/myname/.rbenv/versions/2.1.2/lib/ruby/gems/2.1.0/extensions/x86_64-darwin-13/2.1.0-static/nokogiri-1.6.2.1/gem_make.out
An error occurred while installing nokogiri (1.6.2.1), and Bundler cannot
continue.
Make sure that `gem install nokogiri -v '1.6.2.1'` succeeds before bundling.