Fixed docker build path parameter

Updated the build path to specify the specific docker file to run

.github/workflows/dockerimage.yml

@@ -14,6 +14,6 @@ jobs:
     steps:
     - uses: actions/checkout@v2
     - name: Build the admin_frontend Docker image
-      run: docker build /home/runner/work/buttercup_store/buttercup_store/admin_frontend/Dockerfile --file Dockerfile --tag derkkila/admin_frontend:$(date +%s)
+      run: docker build -f admin_frontend/Dockerfile --tag derkkila/admin_frontend:$(date +%s)
     - name: Push admin_frontend to Dockerhub
       run: docker push derkkila/admin_frontend:$(date +%s)