Fix (?) the build with an image tag for builder

Also I added a base stage so we can have a common working directory.

Dockerfile

@@ -1,29 +1,23 @@
-FROM node:10-alpine as builder
+FROM node:10-alpine as base
 LABEL Description="Backend of the Social Network Human-Connection.org" Vendor="Human Connection gGmbH" Version="0.0.1" Maintainer="Human Connection gGmbH (developer@human-connection.org)"
 
-# Expose the app port
 EXPOSE 4000
-
 ARG BUILD_COMMIT
 ENV BUILD_COMMIT=$BUILD_COMMIT
 ARG WORKDIR=/nitro-backend
 RUN mkdir -p $WORKDIR
 WORKDIR $WORKDIR
-
-# Install the Application Dependencies
-COPY package.json .
-COPY yarn.lock .
-RUN yarn install --frozen-lockfile --non-interactive
-
-COPY . .
+COPY package.json yarn.lock ./
 COPY .env.template .env
-
-RUN yarn run build
 CMD ["yarn", "run", "start"]
 
+FROM base as builder
+RUN yarn install --frozen-lockfile --non-interactive
+COPY . .
+RUN yarn run build
+
 # reduce image size with a multistage build
-FROM node:10-alpine as production
+FROM base as production
 ENV NODE_ENV=production
 COPY --from=builder /nitro-backend/dist ./dist
-COPY package.json yarn.lock ./
 RUN yarn install --frozen-lockfile --non-interactive

docker-compose.override.yml

@@ -2,6 +2,7 @@ version: "3.7"
 
 services:
   backend:
+    image: humanconnection/nitro-backend:builder
     build:
       context: .
       target: builder