Add sass Gemfiles to travis configuration

Author: Rafael Mendonça França

.travis.yml

@@ -14,6 +14,10 @@ gemfile:
   - test/gemfiles/Gemfile-sprockets-2-12
   - test/gemfiles/Gemfile-sprockets-2-8
   - test/gemfiles/Gemfile-sprockets-3-0
+  - test/gemfiles/Gemfile-sass-3-1
+  - test/gemfiles/Gemfile-sass-3-2
+  - test/gemfiles/Gemfile-sass-3-3
+  - test/gemfiles/Gemfile-sass-3-4
   - Gemfile
 
 sudo: false