Ignore Gemfile.lock
Specific Ruby as language in the Travis CI config
Setup Rakefile for running tests

Add Rake as a development dependency and create a task that runs tests.

This also makes 'rake test' the default rake task, so running 'rake' in the root
dir of the project will run tests.
Only test the gem against MRI 2.1.3
Create true always test with minitest

Just to make sure specs are running and pass, create a test that is always true.

minitest/pride for life