Test on Rails 4.2 + Ruby 2.3

[futhr]

[lassebunk]

Thanks for this pr :+1: Can you make it work on Ruby 2.3? It's just the test/unit require that's failing I think.

[futhr]

Think this might fix the failing specs.

matrix:
  include:
    - rvm: 1.9.3
      before_install:
        - gem update --system 2.4.8

(edit)

[futhr]

Seems to work anyway without downgrading rubygems for Travis on 1.9.3