modeset/teabag — pull request #67 by virginia-rodriguez (2013-05-16 21:06:32+00:00)
Title: use File#write instead of File::write that isn't supported by ruby-1.9.2

File::write is not supported by ruby-1.9.2.
Changing code like
File.write(filename, file_content)
to
File.open(filename, 'w') { |file| file.write(file_content) }
will solve the problem and still work for higher ruby versions.

We didn't experience any other issues while using teabag with ruby-1.9.2 (we are using capybara 2.0.3). But maybe if you don't plan to support ruby-1.9.2, it should be specified in the docs.