chore: attach docker archive between jobs.

.circleci/config.yml

@@ -35,13 +35,22 @@ jobs:
           key: v1-{{ .Branch }}-{{ epoch }}
           paths:
             - /caches/app.tar
+      - persist_to_workspace:
+          root: .
+          paths:
+            - /caches/app.tar
   deploy:
     working_directory: ~/app
     docker:
       - image: docker:17.05.0-ce-git
     steps:
+      - attach_workspace:
+          at: /tmp/workspace
       - setup_remote_docker:
           version: 19.03.13
+      - run:
+          name: Load archived Docker image
+          command: docker load -i /tmp/workspace/app.tar
       - run: 
           name: Publish Docker Image to Docker Hub
           command: |