Image build is optimized.

.gitlab-ci.yml

@@ -38,7 +38,8 @@ build:
     - name: docker:dind
       command: ["--tls=false", "--storage-driver=overlay2", "--mtu=1500", "--data-root=/mnt/volume"]
   script:
-    - docker build --cache-from=$DOCKER_REPO --no-cache --progress=plain -t $DOCKER_REPO -f flask_ml_api/Dockerfile .
+    - docker buildx create --use
+    - docker buildx build --cache-from=type=registry,ref=$DOCKER_REPO --no-cache --progress=plain -t $DOCKER_REPO -f flask_ml_api/Dockerfile .
     - docker push $DOCKER_REPO
   only:
     - master