Add dockerfile to build gateway image

api/dockerfile

+FROM node:12.13-alpine As development
+
+WORKDIR /usr/src/app
+
+COPY package*.json ./
+
+RUN npm install --only=development
+
+COPY . .
+
+RUN npm run build
+
+FROM node:12.13-alpine as production
+
+ARG NODE_ENV=production
+ENV NODE_ENV=${NODE_ENV}
+
+WORKDIR /usr/src/app
+
+COPY package*.json ./
+
+RUN npm install --only=production
+
+COPY . .
+
+COPY --from=development /usr/src/app/dist ./dist
+
+CMD ["node", "dist/main"]
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