Add travis config, add travis icon to README

.travis.yml

+rvm:
+  - 1.9.3
+  - 2.0.0
+
+before_install:
+  - "sudo apt-get update && sudo apt-get install libicu-dev"
\ No newline at end of file

Gemfile

@@ -13,7 +13,7 @@ gem 'middleman-gh-pages'
 # Live-reloading plugin
 gem "middleman-livereload", "~> 3.1.0"
 
-gem 'redcarpet', git: 'https://github.com/vmg/redcarpet.git'
+gem 'redcarpet', :git => 'https://github.com/vmg/redcarpet.git'
 
 gem "github-linguist", "~> 2.9.5"
 

README.md

-Slate [![Dependency Status](https://gemnasium.com/tripit/slate.png)](https://gemnasium.com/tripit/slate)
+Slate [![Build Status](https://travis-ci.org/tripit/slate.png?branch=travis)](https://travis-ci.org/tripit/slate) [![Dependency Status](https://gemnasium.com/tripit/slate.png)](https://gemnasium.com/tripit/slate)
 ========
 
 Slate helps you create beautiful single-page API documentation. Think of it as an intelligent, modern documentation template for your API.