Add Markdown linting (#52)

- Also renames `make vale` to `make check`
- Addresses a part of #15

docs/Dockerfile

@@ -14,7 +14,10 @@ RUN apt-get -y update && apt-get -y install gpg emacs curl \
 
 WORKDIR /usr/src
 COPY package.json package-lock.json* ./
-RUN npm ci && npm cache clean --force && rm -f package.json package-lock.json*
+RUN npm ci \
+  && npm install -g markdownlint-cli \
+  && npm cache clean --force \
+  && rm -f package.json package-lock.json*
 ENV PATH /usr/src/node_modules/.bin:$PATH
 
 WORKDIR /usr/src/docs

docs/Makefile

@@ -8,9 +8,11 @@ dev:
 		-p 3000:3000 \
 		-v ${PWD}:/usr/src/docs alcion/docs
 
-vale:
+check:
 	docker run --rm \
 		-v ${PWD}:/usr/src/docs alcion/docs vale --glob='*.md' .
+	docker run --rm \
+		-v ${PWD}:/usr/src/docs alcion/docs markdownlint '**/*.md'
 
 shell:
 	docker run --rm -it \

docs/README.md

@@ -24,6 +24,14 @@ $ make build
 
 This command generates static content into the `build` directory and can be served using any static contents hosting service.
 
+### Check Docs
+
+```
+$ make check
+```
+
+This command will lint all Markdown files and check them for style issues.
+
 ### Documentation Platform Development