diff --git a/.github/workflows/rails-integration-tests.yml b/.github/workflows/rails-integration-tests.yml
index afe54a5..3a7ff4f 100644
--- a/.github/workflows/rails-integration-tests.yml
+++ b/.github/workflows/rails-integration-tests.yml
@@ -42,6 +42,7 @@ jobs:
           build-args: |
             RAILS_VERSION=${{ matrix.rails }}
             MAIL_NOTIFY_BRANCH=${{ github.ref }}
+            RUBY_VERSION=${{ cat .ruby-version }}
           push: false
           tags: mail-notify-integration-rails-${{ matrix.rails }}:latest
           outputs: type=docker, dest=/tmp/rails-${{ matrix.rails }}-image.tar