Merge branch 'gemfile' into 'master'

Switch to using a Gemfile

Closes #8

See merge request !12

.gitlab-ci.yml

@@ -3,8 +3,8 @@ image: ruby:2.3
 test:
   stage: test
   script:
-  - gem install jekyll
-  - jekyll build -d test
+  - bundle
+  - bundle exec jekyll build -d test
   artifacts:
     paths:
     - test
@@ -14,8 +14,8 @@ test:
 pages:
   stage: deploy
   script:
-  - gem install jekyll
-  - jekyll build -d public
+  - bundle
+  - bundle exec jekyll build -d public
   artifacts:
     paths:
     - public

Gemfile

+source "https://rubygems.org"
+ruby RUBY_VERSION
+
+# This will help ensure the proper Jekyll version is running.
+gem "jekyll", "3.4.0"
+
+# Windows does not include zoneinfo files, so bundle the tzinfo-data gem
+gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby]
+

Gemfile.lock

+GEM
+  remote: https://rubygems.org/
+  specs:
+    addressable (2.5.0)
+      public_suffix (~> 2.0, >= 2.0.2)
+    colorator (1.1.0)
+    ffi (1.9.17)
+    forwardable-extended (2.6.0)
+    jekyll (3.4.0)
+      addressable (~> 2.4)
+      colorator (~> 1.0)
+      jekyll-sass-converter (~> 1.0)
+      jekyll-watch (~> 1.1)
+      kramdown (~> 1.3)
+      liquid (~> 3.0)
+      mercenary (~> 0.3.3)
+      pathutil (~> 0.9)
+      rouge (~> 1.7)
+      safe_yaml (~> 1.0)
+    jekyll-sass-converter (1.5.0)
+      sass (~> 3.4)
+    jekyll-watch (1.5.0)
+      listen (~> 3.0, < 3.1)
+    kramdown (1.13.2)
+    liquid (3.0.6)
+    listen (3.0.8)
+      rb-fsevent (~> 0.9, >= 0.9.4)
+      rb-inotify (~> 0.9, >= 0.9.7)
+    mercenary (0.3.6)
+    pathutil (0.14.0)
+      forwardable-extended (~> 2.6)
+    public_suffix (2.0.5)
+    rb-fsevent (0.9.8)
+    rb-inotify (0.9.8)
+      ffi (>= 0.5.0)
+    rouge (1.11.1)
+    safe_yaml (1.0.4)
+    sass (3.4.23)
+
+PLATFORMS
+  ruby
+
+DEPENDENCIES
+  jekyll (= 3.4.0)
+  tzinfo-data
+
+RUBY VERSION
+   ruby 2.3.1p112
+
+BUNDLED WITH
+   1.13.6