chore(install): put all install commands into a single script

.travis.yml

@@ -18,10 +18,6 @@ before_install:
 before_script:
   - sh -e /etc/init.d/xvfb start
 install:
-  - npm install --no-optional
-  - npm install --prefix public/docs/_examples
-  - npm install --prefix public/docs/_examples/_protractor
-  - npm run webdriver:update --prefix public/docs/_examples/_protractor
-  - gulp add-example-boilerplate
+  - ./script/install.sh
 script:
   - gulp $SCRIPT

script/install.sh

@@ -0,0 +1,9 @@
+#!/usr/bin/env bash
+
+set -ex -o pipefail
+
+npm install --no-optional
+(cd public/docs/_examples && npm install)
+(cd public/docs/_examples/_protractor && npm install)
+npm run webdriver:update --prefix public/docs/_examples/_protractor
+gulp add-example-boilerplate