Added sass linting.

linting/sass/Dockerfile

@@ -0,0 +1,17 @@
+FROM node:12-alpine
+
+RUN mkdir /src
+
+RUN npm install npm@5.3 && \
+    rm -rf /usr/local/lib/node_modules/npm && \
+    mv /node_modules/npm  /usr/local/lib/node_modules
+
+RUN npm install -g sass-lint
+
+# Cleanup
+RUN rm -fr /root/.npm /node_modules
+
+WORKDIR /src
+
+ENTRYPOINT ["/usr/local/bin/sass-lint"]
+

linting/sass/sass-lint.yml

@@ -0,0 +1,3 @@
+files:
+    ignore:
+        - 'bulma/**/*.*'