Cache Docker image creation

.gitlab-ci.yml

@@ -11,7 +11,7 @@ docker:
   script:
     - mkdir -p /kaniko/.docker
     - echo "{\"auths\":{\"https://index.docker.io/v1/\":{\"auth\":\"$CI_BUILD_TOKEN\"}}}" > /kaniko/.docker/config.json
-    - /kaniko/executor --context $CI_PROJECT_DIR --dockerfile $CI_PROJECT_DIR/Dockerfile --destination $CI_REGISTRY_IMAGE:latest --destination $CI_REGISTRY_IMAGE:debian
+    - /kaniko/executor --cache=true --context $CI_PROJECT_DIR --dockerfile $CI_PROJECT_DIR/Dockerfile --destination $CI_REGISTRY_IMAGE:latest --destination $CI_REGISTRY_IMAGE:debian
   only:
     - master
     - beta