.travis.yml in html-proofer-0.7.3 vs .travis.yml in html-proofer-0.8.0

@@ -1,4 +1,6 @@
 language: ruby
 rvm:
   - 1.9.3
-  - 2.0.0
\ No newline at end of file
+  - 2.0.0
+before_install:
+  - export NOKOGIRI_USE_SYSTEM_LIBRARIES=true