diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 6247b1b..af1809d 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -9,7 +9,7 @@ jobs:
       - uses: actions/checkout@v1
 
       - name: Build image
-        run: docker build --tag $GITHUB_REPOSITORY .
+        run: docker build . --tag ${GITHUB_REPOSITORY,,}
 
       - name: Show image info
         run: docker images