Trying to update
capybara-webkit if you have this issue:
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.
Please try do the following:
brew uninstall qt brew install qt55 brew link --force qt55 gem uninstall capybara-webkit bundle install
Then you are ready to go.
That's all folks!