diff --git a/.github/workflows/docker-build.yml b/.github/workflows/docker-build.yml
new file mode 100644
index 0000000..62f5375
--- /dev/null
+++ b/.github/workflows/docker-build.yml
@@ -0,0 +1,17 @@
+name: Docker Build
+
+on:
+  workflow_dispatch:
+
+env:
+  DOCKER_BUILDKIT: 1
+
+jobs:
+  build:
+    name: build Docker image for Ruby 2.7.6
+    runs-on: ubuntu-latest
+    env:
+      RUBY_IMAGE_TAG: 2.7.6
+    steps:
+    - name: docker build
+      run: ./build.sh