Can't install pg gem on Mountain Lion

Question

I have been having a lot of troubles with Rails after upgrading to Mountain Lion.

Trying to trouble shoot these and searching for hours on the internet so far I have

Answer 1

After installing Mavericks bundle update was throwing an error on the pg gem.

I use Brew to manage my packages and postgresql was already installed, but still I was getting the 'no pg_config' error.

The fix was to just brew uninstall postgresql, then brew install postgresql. After which I was immediately able to successfully run bundle update.