Add .travis.yml for Travis CI

Author: harding

.travis.yml

@@ -0,0 +1,28 @@
+language: ruby
+rvm:
+  - "2.2.2"
+
+## Allows use of docker-based containers, which are more available than
+## the xen-based (or whatever) VMs, so builds tend to happen sooner
+sudo: false
+
+## Save bundler deps.  Requires sudo: false
+cache: bundler
+
+## Disable external link checking to prevent spurious failures because
+## of other people's downtime. This can also avoid wasting their
+## bandwidth.
+
+## Build all possible jekyll pages for use with link checking.
+script:
+    - make all
+
+env:
+  global:
+    - NOKOGIRI_USE_SYSTEM_LIBRARIES=true # speeds up installation of html-proofer
+    
+# Whitelist all branches
+branches:
+  only:
+  - master
+  - /.*/