Add node version 6 to travis.

Nir Galon · Nir Galon · commit a50e437932da · 2016-09-05T13:09:29.000+03:00
diff --git a/.travis.yml b/.travis.yml
@@ -1,6 +1,7 @@
 sudo: false
 language: node_js
 node_js:
+  - '6'
   - '5'
   - '4'
   - '0.12'
