Error building capybara-webkit

I am trying to install capybara-webkit on ubuntu 12.04, but I get this error:

$ gem install capybara-webkit -v '1.0.0'
Building native extensions.  This could take a while...
ERROR:  Error installing capybara-webkit:
    ERROR: Failed to build gem native extension.

    /home/samir/.rvm/rubies/ruby-2.1.0/bin/ruby extconf.rb
Command 'qmake -spec linux-g++' not available

Makefile not found

Gem files will remain installed in /home/samir/.rvm/gems/ruby-2.1.0@dcaclab/gems/capybara-webkit-1.0.0 for inspection.
Results logged to /home/samir/.rvm/gems/ruby-2.1.0@dcaclab/extensions/x86-linux/2.1.0/capybara-webkit-1.0.0/gem_make.out

Any idea?

Solution

You need qmake, which comes from QT (a dependency of capybara-webkit).

The capybara-webkit wiki has instructions for installing Qt and capybara-webkit on various systems: https://github.com/thoughtbot/capybara-webkit/wiki/Installing-Qt-and-compiling-capybara-webkit