[BE]REFACTOR: CI/CD change to submodule

.github/workflows/back-ci.yaml

@@ -9,23 +9,24 @@ jobs:
   backend-CI:
     runs-on: ubuntu-latest
     steps:
+      - name: Make ssh file
+        run: |
+          mkdir -p ~/.ssh
+          echo '${{ secrets.SSH_CONFIG }}' | base64 -d > ~/.ssh/id_rsa
+          chmod 400 ~/.ssh/id_rsa
       - name: 체크아웃
         uses: actions/checkout@v3
-
+        with:
+          submodule: true
+      - name: 서브모듈 업데이트
+        run: |
+          git submodule update --init config
       - name: JDK 11 설정
         uses: actions/setup-java@v3
         with:
           java-version: "11"
           distribution: "corretto"
 
-      - name: Application YML 생성
-        run: |
-          mkdir -p backend/src/main/resources
-          echo "${{ secrets.APPLICATION_PROD_YML }}" | base64 --decode > backend/src/main/resources/application-prod.yml
-          echo "${{ secrets.APPLICATION_DEV_YML }}" | base64 --decode > backend/src/main/resources/application-dev.yml
-          echo "${{ secrets.APPLICATION_AUTH_YML }}" | base64 --decode > backend/src/main/resources/application-auth.yml
-          echo "${{ secrets.APPLICATION_MAIL_YML }}" | base64 --decode > backend/src/main/resources/application-mail.yml
-
       - name: Cache Gradle packages
         uses: actions/cache@v3
         with: