Merge branch '33-gitlab-ci' into '1.0-jekyll-rewrite'

Resolve "Gitlab CI builds"

See merge request !21

.gitlab-ci.yml

+image: ruby:2.3
+
+variables:
+  JEKYLL_ENV: production
+
+before_script:
+  - cd srctweb/
+  - bundle install
+
+build:
+  stage: build
+  script:
+  - bundle exec jekyll build --trace -d '../build'
+  artifacts:
+    paths:
+    - build

srctweb/_config.yml

@@ -41,7 +41,7 @@ exclude:
 
 # Build settings
 markdown: kramdown
-plugins:
+plugins_dir:
   - jekyll-feed
 
 defaults: