update docker version

Author: rydang

.travis.yml

@@ -3,6 +3,11 @@ services:
   - docker
 script:
   - npm run docker-check
+before_install:
+  - curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
+  - sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"
+  - sudo apt-get update
+  - sudo apt-get -y -o Dpkg::Options::="--force-confnew" install docker-ce
 deploy:
   provider: script
   skip_cleanup: true
@@ -11,7 +16,3 @@ deploy:
       only:
         - dev
         - master
-addons:
-  apt:
-    packages:
-      - docker-ce