Installing Qt to get capybara-webkit running

I started working on a new Rails project today and it seems one of the other devs had upgraded the gem capybara-webkit to version 0.13.1.

This caused me to have issues with Qt since upgrading my Mac to Yosemite (OSX 10.10).

Specifically:

Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension.

    /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/bin/ruby extconf.rb
Command 'qmake -spec macx-g++' not available

Gem files will remain installed in /Users/jonnyhaynes/.bundler/tmp/14436/gems/capybara-webkit-0.13.1 for inspection.  
Results logged to /Users/jonnyhaynes/.bundler/tmp/14436/gems/capybara-webkit-0.13.1/./gem_make.out

An error occurred while installing capybara-webkit (0.13.1), and Bundler cannot continue.  
Make sure that `gem install capybara-webkit -v '0.13.1'` succeeds before bundling.  

I tried to install the gem manually as suggested to no avail.

A quick Google led me to here. Which had a few various solutions.

The one that worked for me was:

brew update  
brew install qt  

I was then able to bundle without issue. Maybe it'll fix it for you too?