Merge pull request mathjax#155 from mathjax/issue152

update .travis.yml

Author: dpvc

.travis.yml

@@ -1,7 +1,16 @@
 language: node_js
 node_js:
-- 'stable'
+  - '4'
+  - '5'
+  - stable
 sudo: false
 script:
   - npm install
   - npm test
+deploy:
+  provider: npm
+  email: [email protected]
+  api_key:
+    secure: Fd/yFRRrLDjleB7QnV/Juncg7dJP193IYOWZaJJFohSfPC3TylhJjUb2bD2fcBUbzM9bLPvhz+XJbWS2YXRGzCWABtyjpZTjO9oEkYBmEuNdVnD9b1j+BCWEEyXfBGF0/WBePRtn8XWQLTPbEJXP9Z2HKOUJJlq4cjTLZ7MHZLw=
+  on:
+    tags: true