Remove troublesome rubies from travis config
Add gemfile lock parser
Add another Gemfile.lock test and tidy up spec
Add version mapper and spec
Add executable and start integration spec
Refactor integration spec to use helper methods
Add test for backing up Gemfile
Executable exit if no Gemfile
Refactor integration specs to capture stdout and stderr
First nasty attempt at getting the integration spec to pass
Get the integration test to pass by writing to Gemfile

The code is filthy, but it works. Refactoring coming up.
Add more integration specs