diff --git a/.circleci/config.yml b/.circleci/config.yml
index f7c264fa..b2fcb55b 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -52,7 +52,7 @@ jobs: # a collection of steps
 
   docs:
     docker:
-      - image: circleci/ruby:2.5.3-stretch-node
+      - image: circleci/ruby:2.7.1-buster-node
     environment:
       NOKOGIRI_USE_SYSTEM_LIBRARIES: true
     steps:
@@ -84,7 +84,7 @@ jobs: # a collection of steps
 
       - run:
           name: Bundle Install.pre - needed for mathematical -> 'asciidoctor-mathematical' gem
-          command: sudo apt-get -qq -y install cmake bison flex libffi-dev libxml2-dev libgdk-pixbuf2.0-dev libcairo2-dev libpango1.0-dev ttf-lyx
+          command: sudo apt-get -qq -y install cmake bison flex libffi-dev libxml2-dev libgdk-pixbuf2.0-dev libcairo2-dev libpango1.0-dev
 
       - run:
           name: Bundle Install.pre - install GraphicsMagick for 'prawn-gmagick' gem
diff --git a/Dockerfile b/Dockerfile
new file mode 100644
index 00000000..84cdc3eb
--- /dev/null
+++ b/Dockerfile
@@ -0,0 +1,16 @@
+FROM circleci/ruby:2.5.3-stretch-node
+# FROM circleci/ruby:2.7.1-buster-node
+
+COPY . /app
+
+RUN node -v
+RUN ruby -v
+RUN bundle -v
+
+RUN apt-get update && apt-get install -y \
+  graphviz \
+  graphicsmagick-imagemagick-compat graphicsmagick-libmagick-dev-compat
+
+RUN cd book/config && bundle install
+
+CMD cd book/config && make VERSION="$(npx -c 'echo "$npm_package_version"')"
diff --git a/book/config b/book/config
index 8d7eb9c3..1216accf 160000
--- a/book/config
+++ b/book/config
@@ -1 +1 @@
-Subproject commit 8d7eb9c34523a92b63164abadf38036ca3088389
+Subproject commit 1216accfbd750b835ba92c196aa20ddd3414c515
diff --git a/package.json b/package.json
index 777f62aa..641276ff 100644
--- a/package.json
+++ b/package.json
@@ -15,10 +15,10 @@
   "scripts": {
     "test": "jest --verbose",
     "watch": "jest --watch --verbose --coverage",
+    "ci": "npx eslint src/ && jest --coverage",
     "coverage": "jest --coverage && open coverage/lcov-report/index.html",
     "coverage:win": "jest --coverage && cmd.exe /C start coverage/lcov-report/index.html",
     "lint": "npx eslint --fix --format codeframe src/",
-    "ci": "npx eslint src/ && jest src/ --coverage",
     "semantic-release": "semantic-release",
     "release:check": "semantic-release --dry-run"
   },