Update README for v0.4.1
Implement version constraints, add --optimistic and --pessimistic flags for version constraint. The default behaviour of the gem is left the same.
Add tests the cover version constraint flags, fix up some bugs, change the --no-install flag because it will be incompatible with --environment flag once it's complete.
Add test to cover a case when adding a gem that already exists in the Gemfile, but without a version number, doesn't fail but adds the gem with a version number to the Gemfile instead
Fix bug where adding a gem that already exists in the Gemfile without a version would not fail, refactor some code in gemfile.rb
Fix a typo, slightly refactor no_version code in gem.rb
Add -o and -p flags as shorthands for --optimistic and --pessimistic flags, respectively. Add tests to cover these new flags
Fix a bug where a game name in the comments would get recognised as a gem in the Gemfile and add a test for that case. Add a rubygems_response_shim for turbolinks. Update the get_current_gem_version method so it only detects version numbers.
Merge pull request #13 from shime/hotfix

A couple of small improvements
Bump to v0.4.5
Update README for v0.4.5