Official Docker image (#46)

* Initial Dockerfile

* Docker added to Readme

* Added Docker to Travis

Dockerfile

@@ -0,0 +1,26 @@
+# https://nextjs.org/docs/deployment#docker-image
+
+FROM node:alpine AS deps
+RUN apk add --no-cache libc6-compat
+WORKDIR /app
+COPY package.json yarn.lock ./
+RUN yarn install --frozen-lockfile
+
+FROM node:alpine AS builder
+WORKDIR /app
+
+RUN addgroup -g 1001 -S nodejs
+RUN adduser -S nextjs -u 1001
+COPY --chown=nextjs:nodejs . .
+COPY --from=deps /app/node_modules ./node_modules
+RUN chown nextjs:nodejs .
+
+USER nextjs
+
+EXPOSE 3000
+
+ENV NODE_ENV production
+
+ENV NEXT_TELEMETRY_DISABLED 1
+
+CMD NEXT_PUBLIC_SITE_DOMAIN=$site_domain yarn build && yarn start