add chrome to gitlab-ci for front-end testing

.gitlab-ci.yml

 test:
   script:
   - apt-get update -qy
-  - apt-get install -y python-dev python-pip sudo postgresql postgresql-client libpq-dev
+  - apt-get install -y python-dev python-pip sudo postgresql postgresql-client libpq-dev libxss1 libappindicator1 libindicator7
+  - wget https://dl.google.com/linux/direct/google-chrome-stable_current_amd64.deb
+  - sudo dpkg -i google-chrome*.deb
   - curl -sL https://deb.nodesource.com/setup_4.x | sudo -E bash -
   - sudo apt-get install -y nodejs
   - npm install