Add common for gems .gitignore.
Remove (already ignored) Gemfile.lock since it's not a valid file in gemspec anymore.
Transition to Rails 4 and Ruby 2.0.

Assuming there is no Rails 3.1 and 3.2 support for these changes.
match w/o explicit HTTP method is not supported.
Flash now uses @discard instead of @used.
Response body is empty string, but not space.
Ignore all .lock files.
Support for multiple Rails versions, starting from 3.1.x
Change test engine definition, so it works in Rails 3.1

::use_relative_model_naming? was introduced in Rails 3.2, so this setup wasn't working for 3.1. Normal engine definition is compatible across all versions.
Match response body for both Rails 3 and 4.
Monkey patch FlashHash in test_helper to get used keys.

Return @used (Rails 3) or @discard (Rails 4) if available.
Move Rails 4 gemfile to main Gemfile.
Update travis config to use main Gemfile for Rails 4.
Remove ruby-debug from gemfiles.
Merge pull request #60 from spectator/rails4

Rails 4 support