Test activemodel 3.2.x, 4.0.x and 4.1.x
Fix path to gemfiles
Merge pull request #35 from lnagel/master

Remove the hard-coded German transliteration rules
Merge remote-tracking branch 'other/add-older-activemodel-support'
Make sure to support ActiveModel >= 3.0
Travis: Test with Ruby 2.1.1