the bundle config for installing nokogiri on yosemite

get nokogiri working on yosemite

## Install libxml2, libxslt and libiconv

$ brew install libxml2 libxslt libiconv

## List the locations of these packages

$ brew list libxml2

``
/opt/boxen/homebrew/Cellar/libxml2/2.9.1/bin/xml2-config
/opt/boxen/homebrew/Cellar/libxml2/2.9.1/bin/xmlcatalog
/opt/boxen/homebrew/Cellar/libxml2/2.9.1/bin/xmllint
/opt/boxen/homebrew/Cellar/libxml2/2.9.1/include/libxml2/ (47 files)
/opt/boxen/homebrew/Cellar/libxml2/2.9.1/lib/libxml2.2.dylib
/opt/boxen/homebrew/Cellar/libxml2/2.9.1/lib/pkgconfig/libxml-2.0.pc
..
``

$ brew list libxslt

``
/opt/boxen/homebrew/Cellar/libxslt/1.1.28/bin/xslt-config
/opt/boxen/homebrew/Cellar/libxslt/1.1.28/bin/xsltproc
/opt/boxen/homebrew/Cellar/libxslt/1.1.28/include/libexslt/ (3 files)
..
``

$ brew list libiconv

``
/opt/boxen/homebrew/Cellar/libiconv/1.14/bin/iconv
/opt/boxen/homebrew/Cellar/libiconv/1.14/include/ (3 files)
/opt/boxen/homebrew/Cellar/libiconv/1.14/lib/libcharset.1.dylib
..
``

## Create a bundle config file using the above lib locations and place it in $HOME/.bundle/config

``
---
BUNDLE_BUILD__NOKOGIRI: --with-xml2-include=/opt/boxen/homebrew/Cellar/libxml2/2.9.1/include/libxml2
  --with-xml2-lib=/opt/boxen/homebrew/Cellar/libxml2/2.9.1/lib --with-xslt-dir=/opt/boxen/homebrew/Cellar/libxslt/1.1.28/
  --with-iconv-dir=/opt/boxen/homebrew/Cellar/libiconv/1.14
``