Add gemfile for rails3.2(activesupport, actionpack)
Ignore specific Gemfile.lock
Add gemfile for rails4.0(activesupport, actionpack)
Test with activesupport v4.0 and actionpack v4.0, and allow failure
Merge pull request #38 from sanemat/feature/rails3-and-4

Test with activesupport v4.0 and actionpack v4.0 on travis-ci, and allow failure