[Feature] - Docker Push / Docker Build CI workflow 추가 (#14)

* feat: 도커 이미지 build & push workflow 작성

* fix: 도커 이미지 허브에 추가하는 과정의 오류 해결

.github/workflows/be-dev-ci.yml

@@ -30,5 +30,14 @@ jobs:
       - name: Build with Gradle
         run: ./gradlew clean build
 
+      - name: Sign in Dockerhub
+        uses: docker/login-action@v1
+        with:
+          username: ${{secrets.DOCKER_USERNAME}}
+          password: ${{secrets.DOCKER_PASSWORD}}
+
       - name: Build the Docker image
-        run: docker build -f Dockerfile --no-cache -t touroot/touroot-api .
+        run: docker build -f ./Dockerfile --no-cache -t touroot/touroot-api .
+
+      - name: Push the Docker Image to Dockerhub
+        run: docker push touroot/touroot-api