Docker compose for testing (#124)

diff --git a/Gemfile b/Gemfile
index 1058dd8..4160c3d 100644
--- a/Gemfile
+++ b/Gemfile
@@ -7,3 +7,4 @@
 versions = JSON.parse(open('https://pages.github.com/versions.json').read)
 gem 'github-pages', versions['github-pages']
 gem "yaml-lint", "~> 0.0.9"
+gem "terminal-table", "~> 1.4"
\ No newline at end of file
diff --git a/Gemfile.lock b/Gemfile.lock
index f31c717..7f1dcec 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -21,18 +21,18 @@
     em-websocket (0.5.1)
       eventmachine (>= 0.12.9)
       http_parser.rb (~> 0.6.0)
-    ethon (0.11.0)
+    ethon (0.12.0)
       ffi (>= 1.3.0)
     eventmachine (1.2.7)
     execjs (2.7.0)
     faraday (0.15.4)
       multipart-post (>= 1.2, < 3)
-    ffi (1.9.25)
+    ffi (1.10.0)
     forwardable-extended (2.6.0)
     gemoji (3.0.0)
-    github-pages (193)
+    github-pages (197)
       activesupport (= 4.2.10)
-      github-pages-health-check (= 1.8.1)
+      github-pages-health-check (= 1.16.1)
       jekyll (= 3.7.4)
       jekyll-avatar (= 0.6.0)
       jekyll-coffeescript (= 1.1.1)
@@ -40,13 +40,13 @@
       jekyll-default-layout (= 0.1.4)
       jekyll-feed (= 0.11.0)
       jekyll-gist (= 1.5.0)
-      jekyll-github-metadata (= 2.9.4)
+      jekyll-github-metadata (= 2.12.1)
       jekyll-mentions (= 1.4.1)
       jekyll-optional-front-matter (= 0.3.0)
       jekyll-paginate (= 1.1.0)
       jekyll-readme-index (= 0.2.0)
       jekyll-redirect-from (= 0.14.0)
-      jekyll-relative-links (= 0.5.3)
+      jekyll-relative-links (= 0.6.0)
       jekyll-remote-theme (= 0.3.1)
       jekyll-sass-converter (= 1.5.2)
       jekyll-seo-tag (= 2.5.0)
@@ -66,22 +66,22 @@
       jekyll-theme-tactile (= 0.1.1)
       jekyll-theme-time-machine (= 0.1.1)
       jekyll-titles-from-headings (= 0.5.1)
-      jemoji (= 0.10.1)
+      jemoji (= 0.10.2)
       kramdown (= 1.17.0)
       liquid (= 4.0.0)
       listen (= 3.1.5)
       mercenary (~> 0.3)
       minima (= 2.5.0)
-      nokogiri (>= 1.8.2, < 2.0)
+      nokogiri (>= 1.8.5, < 2.0)
       rouge (= 2.2.1)
       terminal-table (~> 1.4)
-    github-pages-health-check (1.8.1)
+    github-pages-health-check (1.16.1)
       addressable (~> 2.3)
       dnsruby (~> 1.60)
       octokit (~> 4.0)
-      public_suffix (~> 2.0)
+      public_suffix (~> 3.0)
       typhoeus (~> 1.3)
-    html-pipeline (2.9.1)
+    html-pipeline (2.10.0)
       activesupport (>= 2)
       nokogiri (>= 1.4)
     http_parser.rb (0.6.0)
@@ -118,8 +118,8 @@
       jekyll (~> 3.3)
     jekyll-gist (1.5.0)
       octokit (~> 4.2)
-    jekyll-github-metadata (2.9.4)
-      jekyll (~> 3.1)
+    jekyll-github-metadata (2.12.1)
+      jekyll (~> 3.4)
       octokit (~> 4.0, != 4.4.0)
     jekyll-mentions (1.4.1)
       html-pipeline (~> 2.3)
@@ -131,7 +131,7 @@
       jekyll (~> 3.0)
     jekyll-redirect-from (0.14.0)
       jekyll (~> 3.3)
-    jekyll-relative-links (0.5.3)
+    jekyll-relative-links (0.6.0)
       jekyll (~> 3.3)
     jekyll-remote-theme (0.3.1)
       jekyll (~> 3.5)
@@ -187,7 +187,7 @@
       jekyll (~> 3.3)
     jekyll-watch (2.1.2)
       listen (~> 3.0)
-    jemoji (0.10.1)
+    jemoji (0.10.2)
       gemoji (~> 3.0)
       html-pipeline (~> 2.2)
       jekyll (~> 3.0)
@@ -205,13 +205,13 @@
       jekyll-seo-tag (~> 2.1)
     minitest (5.11.3)
     multipart-post (2.0.0)
-    nokogiri (1.9.1)
+    nokogiri (1.10.1)
       mini_portile2 (~> 2.4.0)
     octokit (4.13.0)
       sawyer (~> 0.8.0, >= 0.5.3)
     pathutil (0.16.2)
       forwardable-extended (~> 2.6)
-    public_suffix (2.0.5)
+    public_suffix (3.0.3)
     rb-fsevent (0.10.3)
     rb-inotify (0.10.0)
       ffi (~> 1.0)
@@ -220,8 +220,8 @@
       i18n
     ruby_dep (1.5.0)
     rubyzip (1.2.2)
-    safe_yaml (1.0.4)
-    sass (3.7.2)
+    safe_yaml (1.0.5)
+    sass (3.7.3)
       sass-listen (~> 4.0.0)
     sass-listen (4.0.0)
       rb-fsevent (~> 0.9, >= 0.9.4)
@@ -243,8 +243,9 @@
   ruby
 
 DEPENDENCIES
-  github-pages (= 193)
+  github-pages (= 197)
+  terminal-table (~> 1.4)
   yaml-lint (~> 0.0.9)
 
 BUNDLED WITH
-   1.16.2
+   1.17.3
diff --git a/docker-compose.yml b/docker-compose.yml
new file mode 100644
index 0000000..396d9b7
--- /dev/null
+++ b/docker-compose.yml
@@ -0,0 +1,9 @@
+version: '3'
+services:
+  jekyll:
+    image: jekyll/jekyll:latest
+    command: jekyll serve --watch --force_polling --verbose
+    ports:
+      - 4000:4000
+    volumes:
+      - .:/srv/jekyll
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