Add Docker configuration.

Implemented graceful stopping.

Dockerfile

@@ -0,0 +1,35 @@
+FROM node:12.4.0-alpine AS build
+
+RUN mkdir -p /build
+WORKDIR /build
+
+# Dependencies to build node-canvas
+RUN apk add --no-cache build-base g++ python cairo-dev jpeg-dev pango-dev giflib-dev
+
+COPY scripts /build/scripts
+COPY webpack-utils /build/webpack-utils
+COPY package.json /build/
+COPY yarn.lock /build/
+
+RUN yarn install
+
+COPY . /build
+
+RUN yarn build:quiet \
+ && rm dist/*.html \
+ && rm dist/stats.json
+
+RUN yarn install --prod \
+ && rm node_modules/.yarn-integrity
+
+
+FROM node:12.4.0-alpine AS app
+
+RUN mkdir -p /usr/src/app
+WORKDIR /usr/src/app
+EXPOSE 3000
+
+COPY --from=build /build/node_modules /usr/src/app/node_modules
+COPY --from=build /build/dist /usr/src/app/
+
+CMD ["node", "/usr/src/app/app.js"]