Updated Gemfile and config for latest version of Jekyll, and CI caching

.gitlab-ci.yml

+# Template project: https://gitlab.com/pages/jekyll
+# Docs: https://docs.gitlab.com/ce/pages/
 image: ruby:2.3
 # define the environment variables
 variables:
   JEKYLL_ENV: production
-# 'bundle' all the required gems for the project
+# Add bundle cache to 'vendor' & untracked files for speeding up builds
+cache:
+  untracked: true
+  paths: 
+    - vendor/
+
+# 'Bundle' all the required gems for the project
 before_script:
-  - bundle install
-# build and deploy the site
+  - bundle install --path vendor
+# Build and deploy the site
 pages:
+  stage: deploy
+  environment:
+    name: "production"
+    url: "https://richard.perry-online.me.uk"
   script:
   - bundle exec jekyll build -d public
   artifacts:
     paths:
-    - public
+    - public/
+    when: always
   only:
-  - pages
+  - pages
\ No newline at end of file

Gemfile

 source 'https://rubygems.org'
-gem 'jekyll', '3.4.3'
+gem 'jekyll'
 gem 'jekyll-theme-perry'
 gem 'flickraw'
 gem 'jekyll-paginate'

_config.yml

@@ -22,7 +22,9 @@ exclude:
   - 'Gemfile.lock'
   - 'LICENSE.md'
   - 'README.md'
+  - 'vendor'
+# Gems/Plugins for site functionality
 plugins:
   - jemoji
   - jekyll-seo-tag
@@ -60,6 +62,7 @@ disqus:
   shortname: richardperry
 # Outputting
+incremental: true
 permalink: /:categories/:title/
 paginate: 10
 paginate_path: "page/:num"