Merge pull request #507 from daming-lu/develop

update IP to new node

.travis.yml

@@ -15,7 +15,7 @@ addons:
       - python-pip
       - python2.7-dev
       - golang
-  ssh_known_hosts: 52.76.173.135
+  ssh_known_hosts: 13.229.163.131
 before_install:
   -  sudo pip install -U virtualenv pre-commit pip
   -  GOPATH=/tmp/go go get -u github.com/wangkuiyi/ipynb/markdown-to-ipynb