Ruby on Rails

ERROR:  Error installing nokogiri:

ERROR: Failed to build gem native extension.

    /Users/bradfordli/.rvm/rubies/ruby-2.0.0-p481/bin/ruby extconf.rb

Building nokogiri using packaged libraries.

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libiconv is missing.  please visit http://nokogiri.org/tutorials/installing_nokogiri.html for help with installing dependencies.

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*** 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

--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/bradfordli/.rvm/rubies/ruby-2.0.0-p481/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

Gem files will remain installed in /Users/bradfordli/.rvm/gems/ruby-2.0.0-p481@railstutorial_rails_4_0/gems/nokogiri-1.6.2.1 for inspection.

Results logged to /Users/bradfordli/.rvm/gems/ruby-2.0.0-p481@railstutorial_rails_4_0/gems/nokogiri-1.6.2.1/ext/nokogiri/gem_make.out

I checked /usr/local/Cellar and I have a libiconv direcotry in there but I always get the error saying libiconv is missing