Fix errors with Homebrew/Ruby in Mac OS X El Capitan

fix-homebrew-mac-osx-elcapitan.sh

# This script aims to fix errors similar to below:
#
#  /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require': cannot load such file ...
# from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
#
# The error is commonly stumbled upon in Mac OS X El Capitan.

# fix access permission issue with the new Mac's SIP process
sudo chown -R $(whoami):admin /usr/local

# try to reset/clean the directories
cd /usr/local
git reset --hard && git clean -df
cd -

# run doctor and update
brew doctor
brew update