Update .gitlab-ci.yml

.gitlab-ci.yml

 image: 'clarinpl/python:2.7'
 
 build_image:
+  stage: build
   image: 'docker:18.09.7'
   only:
     - master
   services:
     - 'docker:18.09.7-dind'
+  variables:
+    DOCKERHUB_NAME: clarinpl/$CI_PROJECT_NAME
+  before_script:
+    - ''
   script:
-    - docker build -t clarinpl/summarize .
+    - docker build -t $DOCKERHUB_NAME .
     - echo $DOCKER_PASSWORD > pass.txt
     - cat pass.txt | docker login --username $DOCKER_USERNAME --password-stdin
     - rm pass.txt
-    - docker push clarinpl/summarize
+    - docker push $DOCKERHUB_NAME
+    - docker login -u $CI_REGISTRY_USER -p $CI_REGISTRY_PASSWORD $CI_REGISTRY
+    - docker image tag $DOCKERHUB_NAME $CI_REGISTRY_IMAGE:$CI_COMMIT_REF_SLUG
+    - docker image tag $DOCKERHUB_NAME $CI_REGISTRY_IMAGE:latest
+    - docker push $CI_REGISTRY_IMAGE