feat(config.yml):add a docker build and push step

I had :
-Build your docker file using the tag app
-Login to docker hub
-Tag your app yourdockerhublogin/my-awesome-ci-expr:BUILDNUMBER (I will let you figure out how to get the build number)
-Tag with yourdockerhublogin/my-awesome-ci-expr:latest
-And finally, push it all to docker hub

.circleci/config.yml

@@ -68,7 +68,26 @@ jobs:
         steps: 
             - checkout
             - restore_cache:
+                name: Restore Yarn Package Cache
                 key: yarn-packages-v2{{ checksum "yarn.lock" }}
             - run: 
                 name: "E2e Test"
-                command: yarn test:e2e
+                command: yarn test:e2e
+    buildandpush_docker:
+        environment:
+            IMAGE_NAME: sipedaniel/my-awesome-ci-expr
+        docker:
+            - image: circleci/buildpack-deps:stretch
+        steps: 
+            - checkout
+            - setup_remote_docker
+            - run: docker image build --tag $IMAGE_NAME:app .
+            - run: docker load -i /tmp/workspace/image.tar
+            - run: 
+                name: Login and Publish to Docker Hub
+                command: |
+                    echo "etienne20045" | docker login --username sipedaniel --password-stdin
+                    docker tag $IMAGE_NAME:app $IMAGE_NAME:$CIRCLE_BUILD_NUM
+                    docker tag $IMAGE_NAME:app $IMAGE_NAME:latest
+                    docker push $IMAGE_NAME:latest
+                    docker push $IMAGE_NAME:$CIRCLE_BUILD_NUM

Dockerfile

@@ -0,0 +1,5 @@
+FROM node:12.18
+COPY ["package.json", "yarn.lock", "./"]
+RUN yarn install
+COPY . .
+CMD ["yarn", "start"]