Merge pull request #13 from XuluWarrior/npm-ci

Install using `npm ci`

.travis.yml

@@ -5,10 +5,14 @@ before_install:
 - npm install -g npm@latest
 
 install:
-- npm install
+- npm ci
 - npm install -g resume-cli
 - npm install --no-save @percy/script
 
+cache:
+  directories:
+    - "$HOME/.npm"
+
 script:
 - npm run build:styles
 - resume serve --resume=example-resume.json --port 5001 --silent &