use kaniko to build container

.gitlab-ci.yml

@@ -1,13 +1,18 @@
 variables:
-    IMAGE_NAME: thallian/cops
+  CONTAINER_NAME: thallian/cops
 
 build:
-    stage: build
-    script:
-        - docker login -u $DOCKER_USER -p $DOCKER_PASSWORD $DOCKER_REGISTRY
-        - docker build -t $IMAGE_NAME:$CI_COMMIT_SHA .
-        - docker build -t $IMAGE_NAME:$CI_COMMIT_REF_NAME .
-        - docker build -t $IMAGE_NAME:latest .
-        - docker push $IMAGE_NAME:$CI_COMMIT_SHA
-        - docker push $IMAGE_NAME:$CI_COMMIT_REF_NAME
-        - docker push $IMAGE_NAME:latest
+  stage: build
+  image:
+    name: gcr.io/kaniko-project/executor:debug
+    entrypoint: [""]
+  script:
+    - mkdir -p /kaniko/.docker
+    - echo "{\"auths\":{\"$CI_REGISTRY\":{\"auth\":\"$(printf "%s:%s" "$CI_REGISTRY_USER" "$CI_REGISTRY_PASSWORD" | base64 | tr -d '\n')\"}}}" > /kaniko/.docker/config.json
+    - >-
+      /kaniko/executor
+      --context "$CI_PROJECT_DIR"
+      --dockerfile "$CI_PROJECT_DIR/Dockerfile"
+      --destination "$CONTAINER_NAME:$CI_COMMIT_SHA"
+      --destination "$CONTAINER_NAME:$CI_COMMIT_REF_NAME"
+      --destination "$CONTAINER_NAME:latest"