improved CI script

.gitlab-ci.yml

 image: ruby:2.3
 
+cache:
+  paths:
+  - .apt
+
 pages:
   before_script:
     - export LC_ALL="C.UTF-8"
     - export LANG="en_US.UTF-8"
     - export LANGUAGE="en_US.UTF-8"
+    # Configure apt chaching
+    - echo $CI_PROJECT_DIR
+    - export APT_DIR=$CI_PROJECT_DIR/.apt && export APT_STATE_LISTS=$APT_DIR/lists && export APT_CACHE_ARCHIVES=$APT_DIR/archives
+    - printf "dir::state::lists    ${APT_STATE_LISTS};\ndir::cache::archives    ${APT_CACHE_ARCHIVES};\n" > /etc/apt/apt.conf
+    - mkdir -p "${APT_STATE_LISTS}/partial" && mkdir -p "${APT_CACHE_ARCHIVES}/partial"
+    - apt-get update -y && apt-get install -yq rsync
     - eval $(ssh-agent -s)
     - ssh-add <(echo "$SSH_PRIVATE_KEY")
     - mkdir -p ~/.ssh
@@ -16,7 +26,7 @@ pages:
     - gem install bundler
     - bundle install
     - bundle exec jekyll build -d public
-    - scp -r public/* git@guides.accessnow.org:/home/git/guides
+    - rsync -av --delete public/ git@guides.accessnow.org:/home/git/guides
   artifacts:
     paths:
       - public